Sienna cheating on Jude? It's called karma!

TALK about a taste of your own medicine... Jude Law has dropped everything to race halfway across the world amid rumours that girlfriend Sienna Miller is a bit too friendly with a younger man.

The fuming actor cut short a family holiday and flew from Paris to Toronto - where she is filming Camille - yesterday to confront Sienna over claims she's been cheating on him with co-star James Franco.

Earlier this week it was reported that Sienna, 24, had been spotted passionately kissing James and that they've been on a string of dates.

Despite her denials in a fraught phone call, 33-year-old Jude - who got caught out last year after having an affair with his children's nanny Daisy Wright - "hit the roof". He accused her of making him look stupid. So she he told him to visit her on-set so he can see for himself the flirting is harmless and there's nothing between her and James, 28.

Although she did admit to Jude that the actor has written poems for her.

Sienna, Jude, come on. It's time. Let it die. Your relationship, that is. How far are you going to let your relationship and the world's respect of you guys deteriorate before you put this thing to rest? Move on with your lives! [Sigh.]