The 31-year-old actress agreed to go out with the gym hunk when she was just 18 and visiting him to lose weight, but the fitness fanatic only asked her out because he wanted to become an actor.
Speaking at a press conference for her new movie `Life As We Know It` - in which she stars with Josh Duhamel - she said: "I was 20 lbs heavier and trying real hard to work it off at the gym and my trainer asked me out. He took me to Sizzler and gave me his head shot and asked me if I could get him in my agency. I knew it wasn`t the extra 20 lbs that turned him on!"
Katherine started her career as a child model and starred in her first movie `That Night` in 1992 when she was just a teenager.
She followed it up with a number of other big screen roles before she reached 20, including an appearance alongside Steven Seagal in 1995 action film `Under Siege 2: Dark Territory`.