Heidi Klum, 51, celebrates her third husband Tom Kaultiz's 35th birthday in Zurich: 'Love of my life!'

Heidi Klum left the comfort of her $9.875M Bel-Air mansion to fly all the way to Switzerland to celebrate the 35th birthday of her third husband Tom Kaultiz at Lake Zurich on Sunday.

At 51, the America's Got Talent judge might be 16 years older than the Tokio Hotel guitarist, but they've been inseparable ever since meeting on the set of Germany's Next Topmodel in their native Germany back in 2018.

Third wheeling it with the married couple of five years, as usual, was Tom's identical twin brother and bandmate Bill Kaulitz.

Heidi - who boasts 24.6M social media followers - captioned her celebratory Instagram post of the touring siblings: 'Loves of my life! 35 years young. Happy birthday!'

The Kaulitz brothers (born Kaulitz-Trümper) have been filming the second season of their Netflix docuseries Kaulitz & Kaulitz, and they'll next bring their band to the Super Bloom Festival in München, Germany this Saturday.

The Home rocker is stepfather to Klum's four children - daughter Lou, 14; son Henry, nearly 19; son Johan, 17; and daughter Leni, 20 - with ex-husband #2 Seal and ex-boyfriend Flavio Briatore.

'The sweetest thing that my partner has done for me is that he asked my kids first if he could ask for my hand, so he kind of was in cahoots with my kids,' the Emmy-winning host recalled to People on August 14.

'They figured out how they were going to do it and then they all surprised me on Christmas morning six years ago. I thought that was so nice that he involved my kids.'

Tom ended his year-long marriage with first wife Ria Sommerfeld in 2016, and Heidi ended her five-year marriage to ex-husband #1 Ric Pipino in 2002.

Last Monday, Klum gave her fans 'a clue of what's to come on October 31' for her next elaborate Halloween costume in the form a of a bloodshot glass eye.

The self-proclaimed 'Queen of Halloween' collaborates with Oscar-nominated make-up artist Mike Marino and his Prosthetic Renaissance team on what to wear at her annual ball in Manhattan.

'I start thinking about it on November 1. I usually have two or three ideas that I'm playing with and then I decide on one thing,' Heidi told DailyMail.com back in 2019.

'So the next morning, I start thinking, "Maybe next year, I'm going to do that one that I didn't do this year." And then, obviously, throughout the year new ideas pop up because maybe I've seen a new or old movie, or was inspired by my travels.'

Klum continued: 'I put a lot of pressure on myself to come up with something better and better every year. I don't want to let the costume lovers down. I know there are so many creative people out there and fans that are excited to see what I do each year.'

The Sunglasses at Night singer currently judges the 19th season of America's Got Talent, which airs Tuesdays and Wednesdays on NBC and Peacock.

Back in 2021, The Cinemaholic reported that Heidi earned $2.5M per season while judge Howie Mandel earned $1.75M, judge Sofía Vergara earned $10M, and producer-judge Simon Cowell earned $45M.