07/31/2009 at 11:00 AM EDT
Watch out, Wonder Woman. Brooke Shields
may give you a run for your money.
"I'm a closet superhero," the 44-year-old super-fit mother of two told PEOPLE with a chuckle when asked how she stays in such killer shape. Shields's real secret: She does a combination of yoga and spinning – and stays away from the dumbbells so she doesn't bulk up.
"It's not safe for me to work with weights at the moment because I just get a bit ... I respond quickly," she explained at a Manhattan launch party for the BlackBerry Tour smartphone from Sprint.
What she's doing in the gym is paying off! And folks on the Boston set of her latest film Furry Vengeance
, also starring Brendan Fraser, certainly have noticed.
"Somebody on the set yesterday just yelled out, 'Does someone have a sewing kit? Because she's ripped,'" Shields said. "I was like, I think I'm flattered?"