Heidi Klum arrived at her own Halloween party in New York on Saturday dressed as a giant, bloody severed hand — her own left hand, complete with long red nails, a thumb ring and her wedding band — and was almost entirely hidden inside it.

The model and television personality, 53, was unrecognisable, with only her eyes and mouth visible and fake blood dripping from her mouth. The top of the costume ended in a gory arrangement of dangling ligaments and tendons, and she was accompanied by helpers in blood-stained hazmat suits.

"It took a lot of hands putting this hand together," Klum told reporters on the red carpet. "I think about 10 or 20 hands."

This year marked the 25th anniversary of the party, which has become one of the most photographed events of the celebrity calendar.

Where the idea came from

Klum said the concept had been forming for a year. "I looked at my hand and I thought, 'Hey, I think that I can fit my body inside of this somehow,'" she said.

"I always try to come up with something unusual and I don't think I've seen an actual person walking around like a hand. I thought that was something new and different."

Getting into it took about five to six hours, she said, while making the costume took far longer. She posted hints on Instagram during the day as bloodied prosthetics were applied to her face.

"Hands down, the hardest thing is carrying it," she said. At the party she later shed the full hand, appearing without it as the night went on.

A history of escalation

Klum's costume has become an annual exercise in one-upmanship against herself. She went viral in 2022 when she arrived at the party on the end of a fishing line, encased in a slithering worm costume.

Past looks include Medusa, a peacock, an eight-foot-tall Transformer, the werewolf from Michael Jackson's Thriller video, a clone accompanied by several Klum lookalikes, and Kali, the multi-armed Hindu goddess of death and destruction. The BBC noted earlier costumes including an ogre version of Princess Fiona from the Shrek films.

The pattern is consistent: the costume is designed to be legible in a photograph, strange enough to be shared, and difficult enough to build that it produces its own behind-the-scenes content in the days before the party.

The guest list as a second show

The party has become a stage for other celebrities' costumes too. This year the actors Neil Patrick Harris and David Burtka came as the twins from the horror film The Shining, the pop star Jade Thirlwall arrived as a stone statue of an angel, and the Severance and Spider-Man actor Tramell Tillman turned up with intricate face makeup and prosthetics, including fake ears and tufts emerging from his forehead.

In London, the broadcaster Maya Jama hosted her own annual Halloween party dressed as Sir Mo Farah, the four-time Olympic champion. Jama told Elle UK she had wanted to dress as a man for years and called Farah a "bald headed icon".

"He's actually sent me all of his real life Olympic outfits, his real, actual medals he won for the Olympics," she said. "His real trainers. He's even done some TikToks for me. He is fully on board."

The comedian Katherine Ryan attended Jama's event dressed as Jama, recreating one of her outfits from Celebrity Traitors, and the singer Lily Allen came as a Ticketmaster seating map covered in unsold blue concert tickets — a costume that read as a joke about the live-music business.

Why these parties matter

Celebrity Halloween has become a small industry of its own. The photographs are commissioned, the outfits are sponsored or built by studios, and the images circulate for days afterwards — long after the party itself is over.

For Klum, the event is a personal brand as much as a party: the costume is the product, and the reveal is the marketing. For guests, attendance buys a place in the same photo set. For the designers and prosthetic artists involved, it is a portfolio piece that can lead to film and advertising work.

The commercial logic is visible elsewhere in the season. Halloween spending has become a significant retail event in the United States, and the weekend's cinema releases were timed to catch the same mood, even as household budgets remain under pressure.

The costumes also feed a wider pop-culture machine in which fan communities dissect every reveal within minutes, and the line between a private party and a public broadcast has effectively disappeared.

The morning after

By Sunday, the images were everywhere: the hand, the hazmat suits, the red nails. Whether the costume will be remembered as one of Klum's best is a matter of taste — the worm has a strong claim — but the machinery worked exactly as intended.

The party is 25 years old, and its formula has not changed: one central, photographable idea, executed at a scale that makes it news. The only thing that escalates is the craft.