The supermodel and executive producer Michael Rucker discuss their homecomings to the series, the dynamic cast and why Christian Siriano remained as the designer’s mentor with the network shift.

The Gist: Klum is indeed back as host, seven years after she and Tim Gunn left the show to produce and star in Making The Cut on Prime Video. However, Gunn wasn’t asked to return alongside Klum; former Runway winner Christian Siriano remains in the mentor role (he did double duty as host and mentor for the past couple of seasons).

Heidi Klum chatted about season 21 of "Project Runway" on "GMA" and revealed a hint about her Halloween costume this year.

Heidi Klum talks about how she can't stop internally judging people, being the queen of throwing Halloween parties and returning to Project Runway.

Summertime florals played a key role in Heidi Klum's attire for her appearance on "The Tonight Show Starring Jimmy Fallon" on Wednesday. The longtime model and "Project Runway" Season 21 host styled a look courtesy of Lebanese designer Rami Kadi Couture.

"Project Runway" season 21 premieres on Freeform July 31 and will be available to stream on Hulu and Disney+ afterward.

Klum joined "Good Morning America" on Wednesday wearing a winning two-piece skirt set designed by a current contestant and shared more details about season 21 of the reality TV series. ABC News - PHOTO: Heidi Klum joins "GMA" to show off the winning dress from "Project Runway" contestants.