Take That stars Robbie Williams and Gary Barlow are competing against each other to see who can lose the most weight before the band's upcoming tour.
The two singers have previously experienced battles with the bulge and Barlow recently admitting he once ballooned to 239 pounds (108.6 kilograms).
But the stars want to be fighting fit ahead of their European tour, which kicks off at the end of May (11) - and Williams is determined to win his bet with Barlow.
He admits he's looking to actor Christian Bale - who shed 63 pounds (29 kilograms) to play a paranoid insomniac in The MAChinist - for inspiration in his weight loss regime.
Williams tells Britain's The Sun, "Me and Gary vary in weight. We go up and down by the week. Gary and the boys were at my house in Los Angeles last week when Gary turns to me and says, 'I won't be needing these clothes soon, do you want them?' - 'cause he's going on a diet. That was the day I thought, 'Right, if you're eating a lettuce, I'm eating half a lettuce.'
"There is now a serious game on to see who can get the thinnest for the tour. You know The MAChinist with Christian Bale? I'm going for Christian Bale."