Credit: Craig Barritt/Wireimage

Clothing optional!

Heidi Klum posed in the nude for an upcoming Project Runway ad campaign, the Hollywood Reporter has confirmed.

The supermodel, 38, agreed to go naked to promote the show's ninth season, debuting this summer on Lifetime, as part of the network's aim to embrace a sexier image and a new definition of the "contemporary woman."

Lifetime president and general manager Nancy Dubuc explained that a nude Klum (who has four kids with husband Seal) will help the network convey a new message "brazen, strong, confident and sexy" women, THR reports.

Klum still has to sign off on the final image, which hasn't yet been release.

Added Dubuc: "It's Heidi F***in' Klum!"