Miller denies Penn affair

Sienna Miller has slammed reports she is cheating on her boyfriend Rhys Ifans with Hollywood star Sean Penn.

Miller and the 'Mystic River' star - who is divorcing wife Robin Wright Penn after 11 years of marriage - were recently spotted cosying up at a New York hotel, reports the New York Daily News.

But the actress has branded the reports "outrageously untrue" and insists the pair are just friends.

A spokesman for Miller says: "Sienna is a very good friend of Robin. She adores and respects Robin."