There is no doubt that Leona Lewis has become a much bigger star since she won talent show the X Factor.

But the fashion-forward singer’s choice of outfit at the weekend certainly didn’t help rumours of her weight gain.

Lewis cut a decidedly dumpy figure in the Ali Baba style jumpsuit she wore to perform at the Capital 95.8 Summertime Ball.

With its clingy fabric which billowed at the ankle and strapless bodice, the London-born singer displayed her curvaceous figure as she took to the stage in the black all-in-one.

It was a rare live appearance in the UK for Lewis, 24, who made the switch to the U.S. this year to record and promote an album.

She has been so busy with her career, that she has even had to turn down invitations from the President of the United States.

The X Factor 2006 winner was put on the guest list for a White House party but was unable to attend because of work commitments.

Her spokesman said at the time: ‘She really wanted to meet him, but it unfortunately clashed with her schedule to get her second album done.

‘Leona has had studio sessions in LA booked for months and has been working day and night getting things perfectly.’

- I don’t care what journalists or reporters say, Leona is fine and rockin’ the way she is. Photos of the event with be uploaded ASAP!