Lily Allen has revealed the secret to her svelte figure - crisps.

The Air Balloon singer, who showed off her toned abs on stage, admitted she has been tucking into the savoury snacks while on the road in Australia.

"I just eat a lot of crisps, I'm not really eating a lot of proper meals while on tour," she told Australian radio station 2Day FM.

The 29-year-old mother-of-two said dancing and her regular work-outs help her remain toned and keeps the weight off.

"I think it's touring and dancing and probably, you know, the not wanting to eat room service thing," she said.

"I don't really like food being mass produced, you look at those kitchens and they're huge, I just don't like it."

Lily, who will support Miley Cyrus on the North American leg of the Bangerz tour, said she preferred to pop to the local supermarket and make her own sandwiches.