Heidi Klum has revealed that Project Runway will open its ninth season this week with a nightwear challenge.
The design competition, which also features Michael Kors and Nina Garcia as judges, returns for its new season this Thursday on Lifetime.
Host Klum said on today's Good Morning America: "For the first challenge, all the designers meet and go back to their apartment and go to bed, then at one in the morning Tim Gunn knocks on the door and says, 'OK, the first challenge is about to happen right now. You have to make an outfit with your pyjamas'."
Klum added: "Some [of the designers] didn't wear much. Some just had little boxer shorts on or a little T-shirt, others had more on. The more they had on the better because they had more fabric!"
Kors joked: "No birthday suits but it teaches you that you better wear a lot to bed!"
Kim Kardashian, Christina Ricci, Zoe Saldana and Malin Akerman are among the celebrity judges for this season.
The winner of Project Runway will receive $100,000 from L'Oreal Paris to start their own fashion line, as well as a fashion spread in Marie Claire magazine, a $50,000 technology suite by HP and Intel to run their business and the opportunity to sell their collection on Piperlime.com
Project Runway premieres Thursday, July 28, at 9pm ET/PT on Lifetime.