Heidi Klum spent 12 hours transforming herself into a gory-looking character from outer space for her annual Halloween party on Thursday (31.10.19).

The 46-year-old model documented her incredible transformation via social media, providing her fans with behind-the-scenes updates as she was turned into something that looked to be part-robot and part-alien.

Heidi - who was joined at the party in New York City by her husband Tom Kaulitz, who dressed as an astronaut for the occasion - told 'Entertainment Tonight': ''I totally lost track of time today. I don't even know how long this took for me today.''

Tom, on the other hand, revealed the inspiration for his own eye-catching costume, and how it related to Heidi's outfit.

He shared: ''So I was on a mission in outer space, looking for a new planet, because we almost destroyed ours.

''So I found her and I brought her back, because I thought she might have some useful information for us.''

Heidi - who was joined at the party at Cathedrale New York by the likes of Ice T, Coco Austin and Dylan Sprouse - decided to give fans a behind-the-scenes look into her costume preparations this year, as she prepared for her party by getting ready in the window of a store in the Big Apple.

The model - whose outfit featured a set of intestines and muscles that poked through her fake skin, as well as tubes coming from her breasts and her hips - previously explained: ''This year is my 20th anniversary of my Halloween party, so I thought it would be fun for people to watch live when I get ready.

''On the 34th Street store of Amazon, I'm gonna be sitting in the window and people can just come by all day long and just watch the process if they're interested in seeing something like that.

''I thought it was fun to do a live art installation - that's what I just want to call it, because for me, it's life art, what they do to me.''

Over the past 20 years, Heidi has worn a number of memorable Halloween outfits, such as in 2018 when she dressed as Princess Fiona from the 'Shrek' movies, and in 2015, when she appeared in the guise of Jessica Rabbit.

In 2001, Heidi even turned up for her party on horseback, as she dressed as the legendary English noblewoman Lady Godiva.