With her eye-catching womanly curves Megan Fox has built up a huge fanbase.

But it’s clear the actress doesn’t take her impressive figure too seriously.

And the actress couldn’t keep a straight face as she stripped off for a scene from This Is 40.

In a newly release outtake from the film Megan is seen been overcome by a fit of the giggles as her co-star Leslie Mann grabs her breasts and jiggles them.

The scene saw Leslie lamenting her aging body, and reaching out to ᴀssess the younger Megan’s perky breasts.

As she shakes them with a ‘wow’, the poker faced 26-year-old suddenly throws back her head and roars with laughter.

Despite wearing nothing more than bright pink underwear, it’s clear Megan obviously didn’t feel uncomfortable filming the scene.

Leslie, 40, reprises the character she played in Knocked Up – boutique shop owner Debbie – in the film directed by her husband, Judd Apatow.

Gorgeous Megan plays her sales employee Desi whose eye-catching ᴀssetsprove too much for Debbie to see and not touch.

In the finished version, Leslie is shown prodding her finger at the actress’s ᴀssets as she questions if they’re real or not.

‘Yeah, I’m just young,’ Megan’s character Desi nonchalantly replies.

And it wasn’t just Leslie’s onscreen character who was impressed.

‘Megan just has great boobs,’ Leslie said in a recent interview with Yahoo! Movies. ‘Better boobs than I’ve ever seen in my life.’