Simon Cowell is not famous for his unbridled praise of amateur singers, but he was clearly taken with his latest protégée last night - a 35-yearold mother of one from Croydon. The X Factor judge was on his feet and cheering after listening to an enthusiastic rendition of Michael Jackson's Billie Jean.

Deep in conversation: Kate Moss and Simon Cowell last night

Perhaps it was because the song was a tribute to the late entertainer. More likely, however, was that the amateur singer in question was Kate Moss.

Karaoke time: Kate gives it her all

Kate's karaoke performance was at the Beth Ditto clothing range launch party at Sketch in Mayfair.

The Gossip singer has designed a collection for high street store Evans.

We're told: "Before Kate started singing she told the crowd, 'This is for you Michael' and started singing Billie Jean on a PlayStation SingStar."

Determined to remain the centre of attention, Kate then dragged Beth up to sing with her. Our spy added: "They sang David Bowie's Space Oddity and Simon Cowell walked in towards the end and gave them a huge cheer."

Indeed, Cowell was so impressed that he and Kate were seen deep in conversation after the performance.

Perhaps the supermodel was trying to secure a record deal.

She certainly has a penchant for grabbing the microphone at any given opportunity, even if it ruf f les a few feathers in the process.

She reportedly annoyed the non-Pete Doherty members of Babyshambles by taking the stage whenever possible - and Alison Mosshart is very keen to keep her in the wings when playing with Kate's boyfriend Jamie Hince in The Kills.

But Kate's persistence is perhaps paying off. She brought the house down two weeks ago at Café De Paris, with a rendition of Summertime backed by Pink Floyd's Dave Gilmour. And last night's karaoke was enjoyed by guests including Sir Philip Green and his wife, Gok Wan, Yasmin Le Bon - and especially Jamie Hince. Our spy said: "When Kate f ini shed, Jamie Hince gave her a huge hug."

Maybe there's room for her in The Kills after all...