Heidi Klum talks about her Halloween fears.

In an exclusive conversation with PEOPLE at the grand opening of Crazy Pizza in New York City on Tuesday, October 29, the 51-year-old model revealed that she gets “anxious” before unveiling her elaborate costumes.

“I always get nervous,” says Klum. “Because there is no real process. For example, I can’t do a proper fitting before I’m inside. Because I still don’t know if it works. And then something happens and I think, “Oh God.” ”

Speaking of her previous mishap with her costume: America’s Got Talent The judge tells the people, “When I was an apple, Seal was and he was Eve.”

“And because I was nine months pregnant and I wanted to make sure nothing happened to the baby or anything like that,” she continues. “So I was thinking about being this Big Apple, but then we forgot how do I get to the party?”

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Klum – who was married to Seal, 61, from 2005 to 2014 – added: “Look, I couldn’t fit into anything, so I couldn’t get through normal car doors. So they had to get me a convertible at the last minute so I could even get in the car and drive there.”

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

Elsewhere in her chat with PEOPLE, Klum talked about how her kids like having 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 does her own things,” she says. “She’s also really into anime. She makes all the wigs herself, you know, like all the pink ones. They don’t just go under.”

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

“She buys all the accessories and then puts on a little mask, you know, but a real, real one,” the proud mother continues. “She (wears the mask) when she’s sanding and building things.”

Klum adds: “So that she doesn’t notice, breathe in all the dust.” But she does things… she does them right. If anyone has the biggest problem with dressing up and stuff, it’s my Lou.”