Charlie Sheen will "absolutely" have a pre-nuptial agreement before he marries Brett Rossi.
The 'Anger Management' actor - who has an estimated fortune of $125 million - plans to be "generous" towards the porn star in the event their marriage doesn't work out, though he doesn't think the financial contract is necessary because he sees her as his "soulmate".
A source said: "Charlie will absolutely be getting a pre-nup, just in case.
"The pre-nup will be very generous for Brett, but Charlie has to protect his finances even though he doesn't think the agreement will be needed, because he believes Brett is his soul mate.
"It's likely Charlie will pay for Brett's legal fees as they work out the details of the pre-nup. For him, this is only a formality. He doesn't think Brett is after his money. This time, it's different."
Charlie's third wife, Brooke Mueller - the mother of his four-year-old twin sons Bob and Max - received a $500,000 payment when the couple wed in 2008 and £300,000 for each year they were married, as well as $100,000 in relocation feeds and $2.35 million for her share in the actor's Beverly Hills mansion.
And the former 'Two and a Half Men' star is expected to be even more "generous" in his agreement with Brett, 24 than he was with Brooke, who he split from after less than three years together.
The source told RadarOnline.com: "Charlie will be a little more generous with Brett in regards to the pre-nup, than he was with Brooke."
Charlie was advised to draw up a pre-nup with second wife Denise Richards but refused, though she does get $55,000 in child support for their daughters Sam, nine, and Lola, eight.
The source explained: "There wasn't any need at that time because he just didn't have a lot of money. The Two and a Half Men money came after the marriage ended
Charlie married for the first time in 1995, to Donna Peele, but they split a year later.

Matt Damon sent Ben Affleck and Jimmy Kimmel a fax of his butt.
The 43-year-old actor hit back at Twitter jibes from his close pals, who have recently teased him over his reluctance to join the social networking site, by sending them a bare-buttock picture.
The friendly teasing began when Jimmy - who often mocks Matt on his late night talk show 'Jimmy Kimmel Live' - shared a link to a charity auction that Matt and Ben, 41, are involved in.
Ben thanked Jimmy on his Twitter page, but the 'Argo' star couldn't help but include some gentle ribbing of his best friend.
He wrote: "I thank you buddy. And @easterncongo & @water thank you. Matt on the other hand? Matt you there? Right. We will fax you."
While the 'Elysium' star isn't a Twitter user, he caught wind of the mocking and sent Ben and Jimmy the humorous fax.
Comedian Jimmy shared the fax - which Matt sent on a letterhead belonging to his and Ben's production company, Pearl Street Films with his Twitter users, writing: ".@BenAffleck - did you see what your 'friend' Matt faxed to us? NSFW (sic)"
The fax reads: "Dear Ben & Jimmy, here's my fax. Love MD."
The hunky star signed off the correspondence by putting his own spin on Twitter hashtags.
He wrote: "Faxtag: KimmelHasManBoobs (sic)"

Davina McCall and Emma Willis have been nominated for Disney's Celebrity Mum of the Year award.
The past and present 'Big Brother' presenters have both been selected as nominees for the 13th annual award - which will be voted on by the public on the Disney for Mums UK Facebook page - with the winner being announced next month.
Disney UK's Anna Hill said: "Being a mum is always a juggling act and we want to recognise the celebrities that the public think are making a great job of it."
The Saturdays singers Frankie Sandford, Una Foden and Rochelle Humes will also be competing against each other for the prize, with 'Strictly Come Dancing' winner Abbey Clancy, 'Britain's Got Talent' judge Amanda Holden, Denise Van Outen, Michelle Heaton and 'Young Blood' singer Sophie Ellis-Bextor completing the list of nominations.
The famous mothers have a total of 15 children between them but Disney also wants to make normal mums feel a bit more special in the run up to Mothers Day in the UK, March 30.
Anna added: "As well as crowning the Disney Celebrity Mum of the Year, we'll also be celebrating great mums from across the UK in the run up to Mother's Day. All mums need a bit of recognition every now and then, whether they're in the spotlight or not!"
Last year's winner, Spice Girl Emma Bunton, spoke about how important the award was to her, saying: "This award is extra special as it's voted for by you the British public, and of course is about the most important thing - being a mummy!"

Oprah Winfrey looked elegant in a mulberry coloured lace evening gown at the EE British Academy Film Awards at the Royal Opera House in London. The iconic talk show admitted to being stitched into the gown in a video on Instagram.

Chiwetel Ejiofor was all smiles ahead of his win as Best Actor for his role in '12 Years A Slave' at the EE British Academy Film Awards in London. The actor looked smart in a tuxedo as he posed alongside his wife, who looked stylish in a ethereal gown.

Samantha Barks opted for a simple cream gown at the EE British Academy Film Awards at the Royal Opera House in London. The 'Les Miserables' actress accessorized with an elegant pearl necklace.

Lupita Nyong'o looked elegant in a floor length green gown at the EE British Academy Film Awards in London, where she was nominated for Best Supporting actress in her role in '12 Years A Slave.'

Brad Pitt and Angelina Jolie looked smart in matching tuxedos at the EE British Academy Film Awards in London. Angelina gave the masculine tailoring a sexy edge by unbuttoning her shirt collar and leaving her bow tie loose.

Amy Adams looked chic in floor length black gown at the EE British Academy Film Awards in London. The 'American Hustle' actress styled her hair into a sophisticated bun.

Fearne Cotton looked regal in a floor length gold sequinned gown at the EE British Academy Film Awards at the Royal Opera House in London, where she had been hosting alongside Dermot O'Leary.

Uma Thurman opted for simple strapless black gown gown at the EE British Academy Film Awards in London. The 'Nymphomaniac' actress styled her hair into an updo and wore a diamante necklace.

Naomie Harris flashed her legs in a daring pink thigh split gown at the EE British Academy Film Awards in London. The 'Mandela: Long Walk to Freedom' actress emphasised her petite waist with a black belt.