Her penchant for racy footwear lately has meant Gwyneth Paltrow's feet are almost as famous as her face.

But on this occasion not even her shapely legs and towering heels could distract attention from her curiously rotund midriff.

With her thigh-grazing, silver dress showing the hint of a bump, rumours are growing that Miss Paltrow could be expecting baby number three.

Blooming swell: Gwyneth Paltrow looking like she might have something to hide as she left Ronnie Scott's on Thursday night

Talk of a possible pregnancy first surfaced in January after the star was admitted to hospital in New York suffering from a mystery illness.

And the 35-year-old, who has two children with Coldplay singer Chris Martin, Apple, four, and Moses, two,  is apparently keen to extend her family.

In an interview with U.S. magazine Harper's Bazaar earlier this month she admitted: 'I may force myself to do it one more time because the result is so worth it.

'And also my dad said to me that his only regret in life was that he had only two children and he didn't have more.'

Speculation has not been helped by the apparent change in Miss Paltrow's usually ultra-slender physique, which she credits to a gruelling workout regime.

Keeping mum: The actress recently revealed she would like more children

The timing would be perfect. The pair have recently finished work on major projects with Paltrow's latest film Iron Man having been released and Coldplay's new album completed.

The Oscar-winning actress was pictured leaving a charity event at Ronnie Scott's jazz club on Thursday night.

She took to the stage to perform a karaoke version of Killing Me Softly, even receiving a standing ovation from the star-studded audience for her efforts.

In typical fashion her husband was not present to see her perform, continuing the couple's determined efforts not to be pictured in public together.

According to one onlooker, the star started shyly, 'but soon got into the swing of it'.

She appeared on stage a second time to sing Hi Ho Silver Lightning alongside Jeff Beck, Jarvis Cocker, Nigel Kennedy and Stella McCartney.

Veteran presenter Bruce Forsyth hosted the event, which was expected to raise £500,000 for the Hoping Foundation in aid of Palestinian children.