5ive's Scott Robinson has branded Nick Lachey a "d**khead".
The 34-year-old singer has hit back at the former 98 Degrees star, who recently labelled the 'Everybody Get Up' hitmakers "the worst boy band of all time" after the two groups butted heads while touring together in the 1990s.
Scott exclusively told BANG Showbiz: "If you want to quote me, the guy's a d**khead!
"The only reason Nick's saying anything is because he's desperate for a bit of press because he's not doing anything at the moment."
Scott's bandmate Sean Conlon appeared to be oblivious to Nick's damning comments in an interview with US talk show 'Watch What Happens Live' earlier this week, and Scott was only too happy to fill him in.
Scott told his pal: "Nick from 98 Degrees - you won't remember them because they were s***e - but Nick was slagging us off to the press saying we were lame. He's the one with the 98 Degrees tattoo!"
The singer added: "If I'm going to be completely honest, the only reason he's saying that is because we were on the Smash Hits tour with him. There were three bands - he was one of them - and 5ive won the tour, so we won the award, so he's upset. He had bigger muscles than me but he didn't have the award."
The 5ive stars also quipped that Nick, 40, is desperate to join 'The Big Reunion' in a bid to boost his career.
Scott teased: "He probably wants to get on 'The Big Reunion' ... he wasn't asked and he's really p***ed off about it. He was on a small telly programme in America and he thought, 'Oh, I know, I'll mention a bigger band than I'm in and get some press.' "
5ive are set to join fellow 'Big Reunion' groups Blue, A1, 911, 5th Story and Damage on The Big Reunion - The Boy Band Tour in October. Tickets go on sale on Saturday (22.03.14).

Sir Mick Jagger finds it "too raw" to return to New York after the death of his girlfriend L'Wren Scott.
The Rolling Stones singer, whose partner was found dead in her city apartment on Monday morning (17.03.14) after committing suicide, flew to Los Angeles yesterday (20.03.14), and is being comforted by his children, including daughter Karis, with former lover Marsha Hunt, in California, who he is "very close" to.
A source told the Daily Mirror newspaper Mick finds 43-year-old Karis a "huge source of comfort" and he is believed to be helping to plan L'Wren's funeral.
The 70-year-old star, who dated the fashion designer for 13 years, will also be joined by daughters Elizabeth, 30, Georgia, 22, and Jade, 42, who is seven months pregnant with DJ husband Adrian Fillary, and Mick's son James, 28.
Jade reportedly managed to obtain special dispensation from an airline to fly to California to be by her dad's side.
A source told The Sun newspaper: "The kids, who call themselves 'Team Jagger', were waiting to hear what it was Mick wanted to do.
"As soon as he decided to head to LA, then they were heading there too.
"Mick will be supported by his whole family after what's been a huge shock."
The 'Brown Sugar' hitmaker and his bandmates - Keith Richards, Charlie Watts and Ronnie Wood - arrived in America from Perth after postponing their tour in Australia and New Zealand.
L'Wren, 49, and Mick had recently purchased a home in New York after he decided to "end his hotel lifestyle" and told of his shock after her death.
The designer was said to be in more than $6million worth of debt and was planning to close her business before she decided to take her own life.

Madonna has flaunted her hairy armpits.
The 'Express Yourself' singer posted a picture of her displaying her right underarm on Instagram and implied her natural look is an artistic statement.
She captioned the picture of her wearing a sexy black bra and brazenly showing off her armpit: "Long hair...... Don't Care!!!!!! #artforfreedom #rebelheart #revolutionoflove. (sic)"
Earlier in the day, the singer had posted another risque photo in which she wore fishnet tights and fetish-style underwear, showing off her bottom.
She captioned the picture "Looking for Love in all the wrong places!" but subsequently removed it.
Madonna also shared a third photo where she posed with a cigarette, but reassured fans she hasn't taken up any bad habits.
She wrote next to it: "Smokin..............#ididntinhale. #icantwait (sic)."
The 55-year-old star's sexy pictures are sure to impress her boyfriend, backup dancer Timor Steffens, 26, whom she met after they worked on a dance project together.
The Dutchman is already even said to be close to her youngest children, Rocco, 13, Mercy James, seven, and David Banda, eight.
A source said: "Madonna was hinting to people that one of the reasons she likes Timor so much is because he's a natural with her children. She isn't really the type to come out and say something like that, but it was obvious. She had a little smile on her face whenever she watched Timor goofing around with Rocco and the other kids."

Paul Walker will appear in 'Fast and Furious 7' through Computer Generated Imagery (CGI).
The movie's lead actor died in a tragic car crash last November halfway through completing the latest instalment of the car racing franchise, but studio heads pressed ahead with the movie using doubles, digital wizardry and voice effects.
A source told the New York Daily News newspaper's Confidenti@al column: "They have hired four actors with bodies very similar to Paul's physique and they will be used for movement and as a base.
"Paul's face and voice will be used on top using CGI."
Final scenes for the film have been shot in Atlanta, Georgia, and co-star Vin Diesel - who plays Dominic Toretto alongside Paul's Brian O'Conner - told how the tragedy had affected the way he tackled his role.
He wrote on Facebook: "The transition into that Dom state of mind has always been an interesting one. Only this time there is added purpose, a collective goal to make this the best one in the series."
Vin also posted a picture of the last scene he shot with Paul, and paid tribute underneath.
He wrote: "There was a unique sense of completion, of pride we shared ... in the film we were now completing ... the magic captured ... and, in just how far we've come ... 'Fast and Furious 7' will be released ... April 10th 2015! P.S. He'd want you to know first."
The last movie in the series, 'Fast & Furious 6', made over $500 million at the global box office.

Pamela Anderson's short hair improved her love life.
The former 'Baywatch' babe - who married poker player Rick Salomon for the second time earlier this year - unveiled a short cropped pixie hairstyle last year and says it has remarkably changed her life for the better in some surprising ways.
She told French magazine Purple: "This haircut convinced a lot more people. It has struck a chord. It amazes me - even in love - how it's changed everything and encouraged real soul connections, less superficiality.
"I told Paul Desmarre of Christophe Salon Beverly Hills to come to my house later and cut it. Three hours later and voila!
"Not to get too personal, but it really helped me get out of a 'situation' that was not right, no matter how hard I wanted to believe otherwise.
"My family and dearest friends didn't bat an eye. I'm surprised we're even talking about this and at all the attention it's generated. I'm grateful, though; the response has been shockingly positive."
The 46-year-old star appears naked in a set of arty photos for the magazine and admits she is still a show off on camera, years after stripping off for Playboy for several cover shoots.
She added: "I'm a bit of an exhibitionist, and I like having the pictures taken. But seeing these was really something different, something we did. It's like a launching pad for what I'll do now.
"While looking at the pictures I was thinking to myself, is that really me? I mean you don't take a bad picture -- people always look their best in your pictures. It still was a shock to see how strong I look."

Tom Fletcher has written a song in tribute to his son, Buzz Michaelangelo.
The McBusted singer and his spouse Giovanna welcomed their first child into the world on March 13 and now Tom has posted the adorable track 'From Bump to Buzz' on YouTube accompanied by a black and white video which shows his wife's bump growing for nine months until Buzz was born.
In the video Tom stands opposite Giovanna holding a guitar and singing, while she's wearing a crop top to show her ever expanding bump and ends with the happy couple holding the little one in their arms.
Tom wrote on Twitter, "Well, here it is..."From Bump to Buzz" (sic)"
including a link to the video.
He then re-tweeted Giovanna's message: "So... I've been busy growing a little something over the last nine months... here's our 'something new'. Xxx (sic)"
Among Tom's lyrics are the lines: "There will come a morning you will open up your eyes, but it's what you do until that day arrives.
"You want to touch a mountain, taste the waterfall, you only have to see one, than you've seen them all.
"Gonna bet that tomorrow, that the sky is blue. I guess I'm ready, I think I'm ready, I hope I'm ready, for something new."
The musician is adjusting to parenthood and is surprised how quickly time has flown by since Buzz was born.
He added: "Buzz is now officially 1 week old. They grow up so fast! (sic)"

Samuel L. Jackson joked about learning his 'Captain America: The Winter Soldier' lines with one hand covering his eye.
The 65-year-old actor plays S.H.I.E.L.D director Nick Fury, who wears an eye patch over his left eye in the superhero film, and admitted he had difficulty adjusting his sight to read the script when he was in costume.
Talking at the film's press conference at London's Dorchester Hotel yesterday (20.03.14), he told BANG Showbiz: "I've learned to turn my head further, actually. The interesting thing about the patch, that I didn't discover until Captain America, the first one - coz I never had never many lines to say - was when I all of a sudden had dialogue and I would learn it the night before, when I got to work I could only see half the page when I put the patch on. So, I have discovered I have to learn my lines now with one hand covering my eye so my mind will absorb what's going on in there. "
Jackson also hailed army soldiers, who he views as society's real life heroes, since they risk their lives for the benefit of others.
He added: "The young people who put their lives on the line for us, so that we do have the freedom to make movies like this and tell stories like this, because we do have a volunteer army now, it's not like people have to do it. Those young men and women who go out there, put their lives on the line, and go to different countries. They make sure we can do what we do I admire them greatly."

Anthony Mackie is in talks to join the cast of 'Triple Nine'. The 35-year-old actor is in negotiations to join a star studded cast which includes '12 Years a Slave' star Chiwetel Ejiofor, Labor Day's Kate Winslet and model Gal Gadot in Open Road's co...

Kylie Minogue's next tour will be more "streamlined".
The 'Into the Blue' singer is known for her show-stopping, lavish tours, but she has now decided to strip back the production on her upcoming 'Kiss Me Once' Tour and has taken inspiration from the intimate feel of her own house.
She explained: "I'm currently obsessed with this kind of 1970s, soft-focus sexiness - I mean, I'm on the verge of putting a brown-orange sofa and maybe an orange lamp in my house.
"My shows have a reputation for being over-the-top, but I really want this one to be more streamlined, with more of that vibe.
"There will probably still be glitter and feathers. I just definitely don't think bigger is necessarily."
The pint-sized star parted ways with her manager of 25 years, Terry Blamey, last year to join Jay Z's Roc Nation, and she claims it was the "perfect time" to switch management teams.
Kylie, 45, told the Metro newspaper: "I used to joke with Terry that they might as well pickle us, we'd worked together so long. So to change was a big deal but it was totally harmonious. It was the perfect time to wrap it up."

Shakira "bosses" Jay Z about.
The 'Hips Don't Lie' hitmaker, who will release her self-titled 10th studio album on Monday (24.03.14), her first record since signing to Jay Z's Roc Nation label, insists the 'Holy Grail' hitmaker does not tell her what to do.
She told The Sun newspaper: "He's not my boss. He is my manager. In fact he says that I boss him around.
"But he is a great manager. He is very chilled, which is important.
"I think male managers are very relaxed and they know how to handle very stressful situations.
"The thing with women is we give so much importance to every little detail. Everything has the same level of importance. We lose perspective, or at least I do.
"The hairdresser didn't turn up! Arrrrrgggghhh, what can I do? It's the end of the world!
"Where's men's minds don't work like that so they have to prioritise so that puts things in perspective."
Shakira, 37, thinks women can be more "hysterical" when things go wrong and they "lose it" more than men.
She explained: "But Jay Z, in particular, keeps his cool, which is great for me because with a female artist's career there is always some chaos."
'Shakira' is her first English-language album since 'She Wolf' was released in 2009 and her first as a working mum, after giving birth to 14-month-old Milan, her son with FC Barcelona player Gerard Pique.
She added: "It's exciting to be back. A bit scary and exciting at the same time and I honestly don't know how I do it. Only we women can multitask in the way we do. Men would never be able to juggle in the same way."

Britain's Duke and Duchess of Cambridge have hired Spanish nanny Maria Teresa Turrion Borrallo to care for their son Prince George.
The royal couple are "delighted" the full-time child minder has agreed to join their household and will be assisting them during their 19-day trip to Australia and New Zealand next month.
A spokesman for Kensington Palace said: "Maria is a full-time nanny, who started work with us recently, and will be accompanying the Duke and Duchess and Prince George to New Zealand and Australia.
"We will not be giving further details on Maria or her employment, except to say that the Duke and Duchess are of course delighted she has chosen to join them."
Maria trained at the prestigious Norland College in Bath, which teaches nannies how to care for children during an intensive full-time three-year degree course, costing a total of £36,000.
The nannies are taught how to deal with potential kidnappers with the use of their Tae Kwon-Do skills, intruding paparazzi, and how to drive at high speed in any weather conditions.
Maria, thought to be in her 30s, has been working for the royal family for the past few weeks.
The couple recruited the new child minder to look after eight-month-old George after Jessie Webb, 71, who previously looked after William when he was a child, gave her notice in last month.

Johnny Vegas is to return to 'Benidorm'.
The 42-year-old comedian - who starred in the ITV show from 2007 to 2009 - is set to make a comeback to the sitcom next year as his well-loved character Geoff Maltby, alongside Crissy Rock, who will play Janey York again, and Elsie Kelly as Noreen Maltby.
Show favourites Sherrie Hewson, who plays manageress Joyce Temple Savage, Tim Healy, who plays Les/Lesley, and Jake Canuso, who plays hunky bar worker Mateo, will return to the Spanish Solana resort as usual.
The ITV director of entertainment Elaine Bedell said:"After another successful run on screen we're thrilled that a new series is about to start shooting on location in Spain.
"We're equally pleased that some familiar faces from the Solana's past will be making a welcome return to the sunshine."
Meanwhile, Sheila Reid who has played acid-tongued, chain-smoking Madge Harvey in all six series is set to leave the show next year along with her co-stars Siobhan Finneran, who plays her on-screen daughter Janice Garvey, and Steve Pemberton, who stars as her long-suffering son-in-law Mick.
Their teenage son Michael - played by Oliver Stokes - is also being written out, but script writer Derren Litten has promised the well-loved family will leave on a high.
A source told The Sun newspaper: "It's a huge shame the Garveys are leaving because they've been in every series and the fans love them, but writer Derren Litten is excited about their exit storyline.
"He wants them to leave with a bang -- though he'll definitely leave the door open for them to return."