JENNIFER ANISTON's boyfriend JOHN MAYER has poked fun at her ex-husband BRAD PITT in a new online video.

Aniston divorced Pitt in 2005 and began dating rocker Mayer last year.

And now Mayer has taken a swipe at her movie star ex - ridiculing his critically acclaimed new movie The Curious Case of Benjamin Button in a spoof motivational speech posted on videosharing website YouTube.com.

The singer tells the camera, "You're a man of strength, charisma, girth, honour, girth... and influence.

"You know like that guy in the movie the Curious Case of Benjamin Brat, Benjamin Brat, the older you get, the younger you get and right before you die a little tiny-man baby you're gonna discover the ability to time travel into volcanoes.

"I never saw the film, I'm just guestimating that that's how it ends."