The underwear model and pop singer was busy on promotional duties for the Ultimo brand when the wardrobe malfunction occured.

Sarah, who is the face of Ultimo's A-D range, attended an event at Debenhams in London to promote the lingerie, but her top left her exposed when she leaned over to blow a kiss to photographers.

However, the star carried on as normal and was her usual cheeky self, looking very glamorous as usual.

But given her diet, girls all over the UK are likely to be rather envious of her perfect figure.

"I like McDonald's burgers and Happy Meals," she told the Daily Mail. "And I've got a thing for kebabs, too."

Meanwhile, the face and body of Ultimo's D-G collection, Gemma Atkinson, is busy in the Australian outback taking part in the latest series of I'm a Celebrity … Get Me Out of Here.

As yet, however, she has kept her assets firmly under wraps. She is starring in the reality show alongside ex-supermodel Janice Dickinson and Cerys Matthews, among others.