Lily Allen has been told she needs bigger breasts to succeed in the US.

The 'Fear' singer is reportedly furious after it was suggested she undergo surgery to boost her assets.

A source said: "Lily's real hang up is about her boobs. She dropped so much weight in the last six months and it left her almost flat-chested, which has made her feel miserable.

"Before one of her US shows, someone suggested a really great plastic surgeon to her, saying she needed bigger breasts if she wanted to make it as a pop star.

"Lily was furious, saying she would never be so stupid as to have surgery."

The source added to Britain's Closer magazine: "Later, she started asking about the different types of boob jobs."