Kate Moss and Sienna Miller reportedly had a blazing row at a friend's wedding reception on Saturday (22.09.07).
The supermodel is said to be furious about her Welsh actor friend Rhys Ifans' rumoured romance with Sienna and her displeasure came to the boil at the bash.
Kate, 33 - who arrived at the party in London with new boyfriend Jamie Hince and best friend Sadie Frost - was reportedly livid when Sienna, 25, turned up with Rhys.
The two women reportedly spent the early part of the evening exchanging evil glares across the dancefloor but after a few hours of drinking they decided to confront one another.
A fellow guest is quoted by The Sun as saying: "Kate
accused Sienna of stealing her style. She was ranting on about how Sienna was trying to steal her lifestyle and her friends too.
"It was really cutting and everyone was listening to them.
"A few drinks had been sunk by the time Kate said it and Sienna plucked up some courage too. She gave Kate as good as she got."
The rowing pair were pulled apart by Sadie - who was once married to Sienna's ex-fiance Jude Law - who told them to show some respect for the newlyweds.
The onlooker added: "Sienna was in the mood for carrying on the fight but Rhys persuaded her to call it a night."
Sienna was first linked to Notting Hill star Rhys last month after the pair were photographed on holiday together.