She has always been known for her sexy curves, which she flaunted on the Victoria's Secret runaway for years.

But Heidi Klum looked decidedly more lean today as she stepped out in a daring black halter-neck jumpsuit for the Project Runway Spring 2012 Fashion Show in New York. The 38-year-old mother-of-four's sparkling ensemble revealed her noticeably thinner arms and flatter chest.

While the supermodel has always been slim, it appeared that most of her curves had disappeared. Heidi paired her look with towering stilettos, giving her 5'9 frame even more of a boost. The German model went sultry with her make-up; applying a smokey eye and dark vanished finger and toenails. She also wore her shoulder-length hair out in a messy bedhead style, and slipped on a jangling of bracelets.

Heidi was joined by fashion designer Michael Kors to watch the Season Nine finalists of her hit show made their presentations at Manhattan's Lincoln Center. The winner of the reality contest will be announced when the last episode airs in six weeks time. Heidi's new svelte figure is most likely down to her daily jogs. She has been pushing herself to the limit running around the Big Apple this past summer in an effort to encourage people to get fit.

Heidi upped her fitness regime in for a challenge that she set on her website. The supermodel signed up to the AOL Summer Run campaign to encourage people to get out and get fit. She said: 'After running many miles, making lots of new running buddies, and pushing myself to the limit the Summer Run is over! But don't think that I'm going to stop all my new healthy habits just because I won't be tracking my miles anymore. And I hope you don't either!'

Source.Dailymail.co.uk