Justin Timberlake's Rep Slams Cheating Rumours

Justin Timberlake's representative has blasted rumours he's cosying up to movie co-star Mila Kunis behind his girlfriend Jessica Biel's back.

The singer-turned-actor has been shooting Friends With Benefits with Kunis in Los Angeles and the pair has been snapped laughing and joking around on several occasions after the cameras have stopped rolling.

Their close relationship has sparked speculation there's more to their friendship than it seems - but Timberlake's spokesperson has shot down the claims, telling Us Weekly magazine there is "absolutely no truth" to the reports.