Tim Gunn Recalls Heidi Klum 'Getting Ready' in Iconic Worm Halloween Costume: ‘It Was Really Strange’ (Exclusive)

Tim Gunn remembers being in the room while friend Heidi Klum prepared one of her most iconic Halloween costumes of all time.

Speaking with PEOPLE at the Rooftop Happy Hour: Halloween Edition with Tim Gunn, an annual event and Halloween costume parade hosted by the New York Public Library, on Oct. 25, Gunn shared what it was like to be with his former Project Runway co-host as she was "getting ready" for her Halloween parties, including in 2022, when she famously returned to the event post-pandemic dressed as a worm.

“It was at a point where no one knew what she was actually going to be doing except for her makeup people,” Gunn tells PEOPLE. “And I couldn't tell. Just that it was really strange.”

Klum’s costume included a curved head, long tail and realistic ridges that covered her entire body, except for her eyes and mouth. Klum’s husband, Tom Kaulitz, accompanied her dressed as a fisherman.

“The year that she was the worm [was] the first time that I actually interacted with her hair and makeup people because they were making these prosthetics,” Gunn says. “And they said, ‘We told her we can't do this. This is entirely too ambitious.’ But they did.”

In addition to Project Runway, Gunn and Klum are also collaborators on the Prime Video reality show Making the Cut. The model has brandished elaborate Halloween costumes over the years, including Jessica Rabbit, a werewolf and an old lady.

Gunn also noted how “uncomfortable” the worm costume must have been, and recalls Klum walking the red carpet at her party that year.

“She sort of wrestles her way around,” Gunn says. “I mean, I said to her afterwards, ‘If you were to have fallen over, you would never have been able to get up.’ And she said, ‘I did fall over and I had a lot of help getting up.’”

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Gunn also says that despite Klum’s many noteworthy Halloween get-ups, he doesn’t have a personal favorite.

“I love all of Heidi's costumes. I mean, I don't want to sound like I'm just being politically correct. They're always so different,” Gunn says.

“I have no idea what she's doing this year,” he adds. “She does love Halloween. And usually the day after Halloween, she's plotting and planning for next year.”

Gunn served as a judge, alongside librarians for the New York Public Library, during the NYPL costume parade. The annual event invites New Yorkers to dress up in literary-themed costumes inspired by their favorite books, poems, characters and authors. Gunn has served as a judge since 2017.

Gunn, who is also the author of books like Gunn’s Golden Rules (2010), Tim Gunn’s Fashion Bible (2012) andTim Gunn: The Natty Professor (2015), says that while he doesn’t dress up for Halloween himself, there is one bookish costume he would wear if he were to participate in the parade.

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“I would probably come as Edgar Allen Poe,” Gunn says, adding that, “I think he's inextricable from Halloween in many ways.”