Heidi Klum Admits She Gets ‘Anxious’ Ahead of Halloween Costume Reveal: ‘There Is No Real Trial’ (Exclusive)

Heidi Klum is opening up about her Halloween fears.

Speaking exclusively to PEOPLE at the grand opening of Crazy Pizza in New York City on Tuesday, Oct. 29, the model, 51, revealed she gets “anxious” before revealing her elaborate costumes.

“I always get anxious,” Klum says. “Because there is no real trial. like, I can't do a real fitting before I am in it. Because I never know if it works until the day [of]. And then you know, and then something happens and I'm like, ‘Oh god.' ”

Speaking about a previous mishap with her costume, the America's Got Talent judge tells PEOPLE, “When I was an apple, like, you know, Seal and he was Eve.”

“And because I was nine months pregnant, and I wanted to make sure nothing can hurt the baby or something,” she continues. “So I was thinking about being this big apple, but then we forgot how am I gonna get to the party?”

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Klum — who was married to Seal, 61, from 2005 to 2014 — adds, “Look, I couldn’t fit in anything, so I couldn't get through any normal car doors. So last minute they had to get me a convertible to even be able to get into the car to be able to ride there.”

The German-born star is known for her extravagant Halloween costumes at her annual Halloween party in N.Y.C. Last year she dressed up as a peacock for her bash at Marquee Nightclub.

Elsewhere in her chat with PEOPLE, Klum spoke about how her children like to have creative control over their Halloween costumes. 

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The TV personality, who is now married to musician Tom Kaulitz, shares Leni, 20, Henry, 19, Johan, 17, and Lou, 15, with Seal.

“Yeah, I mean, they have their own ideas. I mean, Lou, especially she makes her own things,” she says. “She's also really into the anime. She makes all the wigs herself, you know, like all the pink ones. They don't just go down.”

She adds, “They have like points and things like that so she does that all by herself. She's pretty talented, I have to say, more talented than me when it comes to building things.”

“She buys all the accessories and then she puts a little mask on, you know, but like a real proper one,” the proud mom continues. “She [wears the mask] when she's sanding things down and she's building things.”

Klum adds, “So that she doesn't you know, inhale all the dust. But she does things ... she does it properly. If anyone has the major block about dressing up and that stuff, it would be my Lou.”