The beauty turned up at the annual style ceremony in London to present her close friend Lily Allen with the Woman Of The Year honour.
Moss giggled through her introduction after admitting she was ''absolutely terrible at these things'' before handing the Smile hitmaker her award.
Her guest turn was the subject of some onstage jest from the evening's host, Irish actor James Nesbitt - and Moss took great offence at the jibe.
As she marched out of the awards, she fumed, "He's so f**king rude! How very dare he? Do you know what, I'm never coming back to these f**king awards again."
Pal Allen tried in vain to calm her down, saying, "He didn't mean it like that, Kate" - but Moss still grabbed boyfriend Jamie Hince and made a quick exit.