Kate Moss and Gwyneth Paltrow butted their beautiful heads while celebrating Sir Philip Green's birthday in Mexico after the clean-living actress reportedly mocked the model's looks.
The blondes were among the showbiz gang who were jetted out to spend four days at a luxury resort in honour of the Topshop mogul turning 60.
But despite the raucous partying and boozing (Sir Phil budgeted for 15 bottles of vintage champagne per head), clean-living Gwynnie couldn't resist taking a jog along the beach.
According to The Sun, the sporty star was too much for hellraiser Kate, who joked about the actress' healthy habit - sparking a stand-off which left the catwalk queen fuming.
A source told the newspaper: "Gwyneth had gone for a jog on the beach before the big birthday bash. Kate was out for a walk, eating crisps, when Gwyneth ran past.
"The spat was the talk of the dinner. Everyone was having a giggle about it. Kate is seen as queen of the cool crowd but not everyone falls into line."
It is not the first time a celeb has dared to take a swipe at Kate in recent weeks - Piers Morgan branded the supermodel a "vile creature" in a recent interview.
He told The Mirror: "She came up to me at some charity thing with Naomi Campbell and gave me a full, haymaking kick.
"And then the next time we had dinner in a restaurant, she was opposite me... and kicked me again. I looked at her and said, 'Kate, why are you kicking me?' She said, 'Because I want to'... And cackled.
"She was completely off her head. And I replied, 'Well, can you just stop kicking me, OK?' She looked blank, and gave me another kick. It was a bizarre conversation.
CELEB PICS OF THE DAY