Kate Beckinsale Flaunts Incredible Figure in Sexy Bathroom Selfie -- See the Pic!

Kate Beckinsale has clearly been working on her fitness!

The 43-year-old actress shared an amazing selfie on Wednesday of her ridiculously toned body, taken during her recent photo shoot for Shape magazine's February cover. Beckinsale sports a black crop top and a pair of white bikini bottoms, flaunting her killer physique.

"Laughing in bathrooms with friends," she Instagrammed.

WATCH: EXCLUSIVE -- Kate Beckinsale Reveals the Secret to Co-Parenting With Ex Michael Sheen

In the accompanying interview, the Underworld star shared her secrets to her slim figure, including avoiding alcohol. "I don't drink alcohol," she revealed. "I feel [its effects] very quickly, so I've never actually had an entire glass of anything alcoholic."

She also, of course, gets plenty of exercise. Beckinsale works out with celeb trainer Gunnar Peterson five or six times a week.

"I start out absolutely dreading it, do an incredibly punishing workout, b*tch about it the whole time and end up feeling 100 percent better when I leave," she admitted. "Working out is basically nature's antidepressant."

NEWS: Kate Beckinsale Says She Was Ordered to Work Out If She Wanted a Part on 'Pearl Harbor,' Says Michael Bay Didn't Find Her 'So Attractive'

ET spoke with the British actress in December, when she shared the secret to co-parenting her 17-year-old daughter, Lily, with her ex, Michael Sheen. Watch below: