AceShowbiz - Kate Beckinsale was left feeling self-conscious about her figure after filmmaker Michael Bay advised her to lose weight when he cast her in "Pearl Harbor".

The 2001 war drama served as the beauty's Hollywood breakthrough, but before cameras began rolling on the project, the Brit - who had just become a first-time mother - was encouraged to shed a few pounds.

"It wasn't great, it didn't make me feel good, and in general, I think women are body-shamed 100 million per cent more than men," Beckinsale told Women's Health magazine.

The actress, who shares now-20-year-old daughter Lily Mo with ex-boyfriend Michael Sheen, soon discovered she wasn't the only one to have her looks judged by Bay - the director previously had her "Pearl Harbor" co-star Ben Affleck undergo dental work for their 1998 film "Armageddon".

"Ben, who'd already done a movie with the director, was like, 'This happened to me. They made me get new teeth,' " she recalled. "And I was like, 'Cool, at least I get to hang on to my actual teeth.' "

The experience marked the first time Beckinsale began actively working out, but now she hits the gym six days a week with her personal trainer, because she relies on the endorphins for her mental and emotional health.

"Now exercise is almost more important to me mood-wise," she explained. "The other aspects feel like a great side effect."

Beckinsale continued, "I'm very connected to my body, so if I'm going to experience stress, I'm probably going to experience it physically. So it's usually a good idea for me to go do something physical to get rid of it..."

And the 46 year old claims her fitness fanaticism has helped her avoid injuries onset: "I haven't been injured while doing an action movie, and I think it's partially from practicing yoga," she said. "But as well as that, I just got into trampolining and it's the great thing... it makes you feel kind of jolly."