For most fortysomething women the prospect of slipping into a bikini alongside a young swimwear model would be a little daunting.

But Jennifer Aniston, as you can see, is no average fortysomething.

In her stunning hot pink two-piece, she was more than a match for her much younger co-star.

Ready for my close-up: Jennifer Aniston and co-star Brooklyn Decker peel off as they film a scene for Just Go With It in Hawaii

The 41-year-old actress showed off a flawless figure as she peeled off to shoot scenes for her latest film, Just Go For It, in Hawaii last week.

With her was swimwear model Brooklyn Decker, 23, the wife of tennis star Andy Roddick.

But perhaps Miss Aniston is not as naturally confident as she seems.

She began a gruelling training regime after hearing she would be starring alongside Miss Decker.

Bottom line: Aniston's exercise regime is paying off

She has flown her personal trainer Mandy Ingber over to the island to help her get in shape.

The pair see one another five times a week for punishing 80-minute gym routines that include yoga, martial arts and running.

As well as power-walking twice a day, Miss Aniston is said to be a fan of Budokon - a martial art-based exercise.

However, she denied claims that she was following a baby food diet.

She said: 'I eat really well and I work out, but I don't starve myself in an extremist way. You're not taking away my coffee or my glass of wine because I'd be devastated.'

In the film, the Adam Sandler plays Dr Patrick Maccabee, a commitment-phobic plastic surgeon dating a girl nearly half his age - played by Decker, 23.

Decker's character Beverly wants to settle down with Patrick, so he lies to her, claiming he's already married with children.

He enlists the help of his receptionist Katherine Palmer, a single mother played by Aniston, to pretend to be his 'estranged wife'.