For her 13th annual bash, held this year at the Dream Downtown hotel in New York City, the supermodel mom, 38, got into the Halloween spirit with her hubby Seal, donning matching monkey costumes to walk the red carpet.
Planning her outfit since July, Klum tells Us Weekly this year's costume -- featuring prosthetic breasts, fake fur, false teeth and face makeup -- was quite an undertaking.
"Getting dressed was not the problem," Klum reasoned at Monday's bash. "It was the makeup. The makeup took almost six hours!"
Enlisting the help of Project Runway alum Nick Verreos to perfect her look, Klum says her monkey costume was an easy choice. "[I was first attracted to] the fabric! I saw it, loved it and I was like, 'Wow. I want to be a monkey. That would be so much fun!' she told Us.
Telling the Associated Press she was the "link between man and ape," Klum added that she was just happy not to have to wear heels for the evening.
Klum and Seal weren't the only stars to go all out for Monday's holiday. Jersey Shore's Vinny Guadagnino came to Klum's bash dressed as Zoolander, the character made famous in Ben Stiller's 2001 flick, while Fergie donned a crown to show off her best Toddlers & Tiaras look.