Washington, May 7 : It seems that actress Cameron Diaz is indeed giving a tough fight to Hollywood heartthrob Ashton Kutcher, when it comes to being fit.
The 30-year-old actor has admitted that he had to struggle hard to keep up with his 'What Happens In Vegas' co-star, as she is much fitter than him.
He has also vowed to start a healthy new exercise regime ahead of working with Diaz.
"Before I started the movie I worked out with a trainer because I couldn't have my leading lady be in better shape than me," Contactmusic quoted Kutcher, as saying.
Kutcher also insists that Diaz's high level of fitness and athletic abilities put him to shame.
"Cameron gave me such a tough time. She'd say, 'Are you still working out? Because I already worked out hard this morning,'" he added.
He also revealed that the fight scenes in the movie are real, and Diaz was more than able to hold her own.
He added, "She's a tough chick. She went for it - it wasn't fake. I got beaten up a little bit, but not too badly.