07/16/2008 at 12:10 PM EDT
Megan Fox had to gain weight for her next film – after her director deemed her too skinny.
"I had to put on size for Transformers II
because [director] Michael [Bay] doesn't like skinny girls," Fox, 22, said. "I had three weeks to gain weight, and I put on 10 lbs."
The actress, who said she got “really scrawny” for her role in the upcoming zombie film Jennifer's Body,
indulged in some of her favorite foods to gain back her curves: "You know Doughboys?" she asked of the trendy Hollywood eatery. "They make that red velvet cake. I seriously have that every night before I go to bed."
"I don’t really eat that healthy," added the actress, who talked to reporters at FOX's Television Critics Association party July 14 (she attended with boyfriend Brian Austin Green, who stars in Terminator: The Sarah Connor Chronicles
). "I have a really bad sugar tooth."
magazine's Sexiest Woman in the World
also said she spends little time working out.
"I’m kind of naturally fit for now," she said. "But I hear when you turn 25 your body changes, so I might be out of luck once I hit that age."
The actress also joked about the secrecy surrounding Transformers II
when asked to describe the film.
"I can't – I'll get fired, and then they'll replace me with Eva Longoria!"