Robbie Williams and Rod Stewart came to blows over Rachel Hunter.
Stereophonics frontman Kelly Jones claims the pair accidentally ran into each other shortly after Robbie started dating Rod's now ex-wife at the Sunset Marquis Hotel in Los Angeles.
Kelly said: "I was having a drink with Rod at the hotel, but while he was in the bathroom I saw Robbie Williams walk into the hotel reception and head through to the bar.
When Rod came back I mentioned it in passing that Robbie was there without thinking.
"It wasn't long after Robbie had started seeing Rod's estranged wife Rachel Hunter. When I mentioned it Rod got up and went to set Robbie straight on a few things. He was rolling up his sleeves when he left. He came back after as if nothing had happened but Robbie didn't hang about."
However, Kelly has defended Robbie - who began dating Rachel in 2002, following her 1999 split from Rod - and even thinks Rod acted a little hastily. He added to Britain's The Sun newspaper: "You know Robbie's alright man. You can't knock him for showing Ms. Hunter a good time."
Kelly and Rod were joined by fellow musicians Slash and Ronnie Wood - who was in 70s band The Faces with Rod, which the pair are rumoured to be reuniting for a series of shows later this year - on the evening out, and Kelly reveals Rod and Ronnie are still good friends.
He said: "Rod and Ron spent the night winding each other up, it was class.
"He's a really good friend Ron. I love him and his wife Jo, they always treated me like family at their home - he is one of the warmest people I've ever met."