WORKING WITH AN EX!

Working with an EX, Their relationship fizzled, but these stars can play nice

Avril Lavigne and Deryck Whibley :  It's not complicated for the singer 25, who filed divorce in 2009 from her rocker husband 30. He's helping produce her fourth album, and she calls him " One of my best friends".

Vanessa Williams and Rick Fox :  Three years after ending their marriage in 2004, the actress 46, and the retired basketball player 40, kissed on Ugly Betty! " It was fun" she said of her Ex's guest spot.

Dave Annable & Emily VanCamp :  Mixing business with pleasure ended in breakup for Brothers & Sisters costars VanCamp 23, and Annable 30, who remained TV Siblings after their 2008 split.

Cameron Diaz & Justin Timberlake :  Back on...screen!! They called it quits of dating in 2007, but the actress 37 and the singer 29, will reunite when they costars in the rom-com BAD TEACHER.