Barbie in a bikini on Sports Illustrated cover

New York - After 50 years of debate over her unattainably perfect figure, Barbie now is unapologetic about her tiny waist and endless legs.

To prove it? The doll, which is made by Mattel, is flaunting her frame in Sports Illustrated Swimsuit's 50th anniversary issue alongside super models as part of a campaign called "unapologetic".

The magazine issue, which comes out on Tuesday, features well-known super models like Christie Brinkley alongside Barbie wearing the black-and-white swimsuit the doll wore when she made her debut in 1959.

Mattel is promoting the feature with a hashtag "unapologetic" on Twitter and a billboard in New York's Times Square.

The campaign is a departure for the 55-year old doll, which has been both beloved as a plaything and criticised as an unrealistic standard of beauty for decades.