AceShowbiz - Mel Gibson's ex-girlfriend Oksana Grigorieva has denied the relationship broke down because of an affair - insisting reports the actor cheated on her are "completely wrong". The couple, who became parents to a daughter last year, began dating after the "Braveheart" star split from his wife, Robyn, in 2006 but the romance only became public in 2009 after Robyn filed for divorce.

The Russian singer/songwriter confirmed the romance ended in April, but refused to divulge the reasons for the split. Gibson was subsequently hit by allegations he cheated on his lover with a Polish porn star - a representative for the actor quickly dismissed the claims and now Grigorieva has hit out at the lurid accusations.

She tells Britain's Hello! magazine, "I can tell you for sure all of this is not true. (The reports are) completely wrong. Sorry!" Grigorieva has also brushed off rumors the relationship ended because Gibson refused to make their union official.

She adds, "Marriage? We never talked about marriage, ever... We didn't talk about it because it wasn't important at the time. Everybody is asking those questions, but how can you answer something you haven't talked about?" Grigorieva is adamant they parted on good terms and are determined to remain friends for the sake of their daughter, Lucia: "It was amicable actually. We're talking, it's friendly."