Oasis guitarist and song writer Noel Gallagher allegedly left the group after Liam insinuated he was not the biological father of his nine-year-old daughter Anais.
Noel Gallagher reportedly quit Oasis because his brother Liam "jokingly suggested" he was not the father of his daughter.
The singer is said to have insinuated that Noel's nine-year-old daughter Anais was conceived when the songwriter's former wife Meg Matthews was having an affair.
The slur outraged Noel, who branded it "unforgivable" and started screaming at his brother as the pair prepared to go onstage at Paris' Rock en Seine festival on Friday night (28.08.09).
An insider told gossip blogger Perez Hilton: "It was a dumb thing to say. They had a big fight when he made the gag. Noel went for him.
"He was in a blind fury. And he still hasn't calmed down."
The fight reportedly ended when Liam smashed Noel's guitar while screaming: "You're no brother of mine!"
Noel stormed out of the backstage area and officially quit the band later that night.
In a statement released on the official Oasis website, he said: "It's with some sadness and great relief to tell you that I quit Oasis tonight.
"People will write and say what they like, but I simply could not go on working with Liam a day longer."
He later added: "The details are not important and of too great a number to list. But I feel you have the right to know that the level of verbal and violent intimidation towards me, my family, friends and comrades has become intolerable."