'Project Runway: All Stars' Sneak Peek: Diane Von Furstenberg Returns as Guest Judge (Exclusive Video)

The designers must create eco-friendly red-carpet gowns in Thursday night's episode.

Diane Von Furstenberg returns to the Project Runway judge's chair this week.

Thursday night's episode of Lifetime's Project Runway: All Stars calls on the designers to create eco-friendly gowns. In this clip, which is exclusive to The Hollywood Reporter, von Furstenberg weighs in on a design by competitor Uli Herzner alongside regular judges Georgina Chapman, Isaac Mizrahi and Carolyn Murphy, who also hosts. (Watch the clip above.)

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Von Furstenberg is no stranger to the Project Runway franchise, serving as a guest judge on the first season of Project Runway: All Stars earlier this year. She also judged the Project Runway: All-Star Challenge, which aired in 2009, and has been a guest judge on the original Project Runway twice.

The iconic designer also has served in the same capacity on the CW's America's Next Top Model in multiple seasons.

Eight designers remain on this season of Project Runway: All Stars, which airs at 9 p.m. Thursdays on Lifetime.

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The network on Wednesday announced a new half-hour special, Project Runway Spotlight: Marchesa, which takes a behind-the-scenes look at the fashion house co-founded by Chapman and Keren Craig. Project Runway Spotlight: Marchesa will debut at 10 p.m. Thursday, Dec. 20, following a new episode of All Stars.

Project Runway: All Stars is produced by The Weinstein Co. and Bunim/Murray Productions.