Harry Styles stands "an inch taller" after going to pilates classes for 18 months to help his posture.
The One Direction star, who previously revealed he has one leg around half an inch shorter than the other, has reaped the benefits from attending the physical fitness sessions to help straighten out a bad back.
A source said: "It’s really had a huge impact on his stature and he stands much straighter.
"He seems to stand an inch taller now. He was amazed at the results. If he hadn’t done anything about it, the slouch could have got worse over time but the pilates classes really do seem to be helping."
The 22-year-old hunk was initially encouraged to do ballet to help his posture but started attending yoga classes instead before moving onto pilates, despite not always being able to do one class a week due to his commitments with the boy band.
The source added to the Daily Mirror newspaper: "The past year and a half has seen him gradually make a vast improvement. Obviously pilates has other health benefits too."
Harry spoke about his back issue in 2013 in a TV interview, during which is 1D bandmates teased him about the injury and insisted he blamed it on a demanding paper round during his younger years.
He said: "I have a bad back and I went to see and osteopath. He told me to do ballet.
"But I didn’t. I’m doing yoga instead."