Justin Timberlake Romancing Scarlett Johansson  1/11/07

Justin Timberlake has reportedly already moved on from his split with Cameron Diaz and is romancing Scarlett Johansson.

The My Love singer recently separated from Diaz after three-and-a-half years and has quietly started dating actress Johansson.

According to American publication Us Weekly, Timberlake, 25, and Diaz, 34, called it quits just before the New Year (07).

A source close to Timberlake says the final straw in the relationship came when Diaz became furious after discovering he had handpicked Johansson to star as his love interest in his new music video What Goes Around.

Diaz reportedly dislikes Johansson because she starred in Lost in Translation, a film where Anna Faris plays a ditzy character that was reportedly based on Diaz, and because Johansson subsequently dated her ex-boyfriend Jared Leto.

Johansson, 22, is newly single after a split with her The Black Dahlia co-star Josh Hartnett and was spotted with Timberlake at an after-party for his new film Alpha Dogs last week (03JAN07).

Sources in both stars' inner circles confirm they are in the beginning stages of a relationship.

A source adds, "He sees he has more in common with Scarlett and just thinks she's really cool. They're both just having fun."