Heidi Klum feared that she was going to suffocate in her worm costume.

The 49-year-old model wore the extraordinary outfit at her annual Halloween party and revealed that she asked her husband Tom Kaulitz to make sure she was in a certain position at all times.

Heidi told Entertainment Tonight: "I had to roll everywhere. I just said to my husband, 'Please don't leave me flat on my face and suffocate', because I was worried that I was gonna, at some point, not have any gas left.

"I was worried to be, like, stuck like this, and not be able to breathe and they forget about me. Crazy things go through your head."

Heidi explained that the costume posed other challenges as it left her sweaty and struggling to hear.

The 'America's Got Talent' judge said: "It was strange to be in there, I have to say, because no one can really hear you.

"You can't really hear anyone because it's like this. Everything is muffled at all times. So it's all tight in there and it's boiling hot in there. Like, literally it's a shower. It's dripping, dripping, dripping and yeah, you can't do anything. You can't scratch, you can't point."

Klum revealed that her ultimate aim was to spread some happiness with the remarkable costume.

She said of the reaction: "They were like, 'This is the funniest thing I've ever seen.' So, that just makes me happy, that I could put a smile on everyone's faces, you know?"

Heidi's fellow 'American's Got Talent' judge Howie Mandel found the outfit "scary".

He said: "It was scary. I've said to Heidi, you're a supermodel, you could look good in anything, and then she just proved me wrong. I mean, it was a great costume, but I wouldn't look and that go, 'She looks terrific!'"