Heidi Klum has started building her Halloween costume

Taking to her Instagram account, Heidi uploaded a video of her standing in her bra, knickers and a pair of heels while a member of her team took her measurements.

She captioned the black-and-white clip: "HALLOWEEN preparation ..... don't move a muscle!!!!!!!!!! #heidiklumhalloween #heidiklumhalloween2019 (sic)"

Although some of her fans were shocked by how early she's planning her outfit, Heidi certainly likes to get ahead of the game when it comes to Halloween as she usually starts drawing up ideas for the eery holiday four months in advance.

She said previously: "I like to keep it fun, you know. I usually start planning in June. It's not just going to be just getting dressed easily, I always have a lot of prosthetics done with these amazing people that do this for me."

Last year, the German model - who hosts her own star-studded Halloween bash each year - transformed into Princess Fiona from the Dreamworks movie series 'Shrek', with her now-husband Tom Kaulitz by her side as the titular ogre.

She said at the time: "It's special that I finally found my Shrek. I kind of always wanted to be Fiona, but I never had the Shrek to do it with.

"It is so sweet that he's actually doing this. I've done this many times, doing prosthetics and all of this stuff, so for him to go through this is pretty phenomenal."

This year will mark the 20th anniversary of Heidi's annual Halloween bash and she desperately tries to outdo herself every time, which can be risky at times.

She said: "In the beginning stages, I didn't know about these [prosthetics] professionals yet and I did my own hair and make-up, and I had some people who would help me put the clothes together. When you do prosthetics and all of this stuff, I'm always having my fingers and toes crossed that it actually does work out on the day because there was no dress rehearsal. Because we can't actually glue all these things down and see if it actually really works. So it's always a bit nerve-wracking for me, too, that it actually does work out in the end. Usually it does, but you just never know until the day comes."