“Anthony is a lot taller in-person than on TV and his grip strength is unreal,” said Tesa Ho, Hong Kong’s first female black belt. “He definitely has the Renzo Gracie style with solid fundamentals and a great no-gi leg attack game.

Bourdain is a confessed jiu-jitsu addict. Every day he is home in New York, he takes an hour long class with his principal instructor Igor Gracie, before another hour of working on techniques and drilling, and then sparring, at the Renzo Gracie Academy in Manhattan.

“I used to hang around cold stairwells first thing in the morning waiting for dope. Now I hang around cold stairwells waiting for jiu-jitsu,” Bourdain wrote in a 2015 blog post.

“When I’m not in New York, when I’m on the road shooting Parts Unknown, I go to whatever local gym, yoga studio, garage, cellar claims to teach Brazilian Jiu-Jitsu – places where the term ‘parts unknown’ can really apply. Until I walk in the door, I have no idea what I’ m going to face.”

He has been training jiu-jitsu for more than five years and said being awarded his blue belt “was, other than the birth of my daughter, pretty much the greatest day of my life”.

Bourdain even admitted the Bay Area episode of Parts Unknown was built around his ambition to train at San Francisco’s Ralph Gracie Academy with their legendary black belt, Kurt Osiander.

“The guy is legit. Anthony is a blue belt but he really trains hard,” purple belt Patricio Reyes, another Hurt Locker patron, said.

“He’s really fit, even though he has a normal life – because he drinks and smokes and eats a lot, everything you see in his show.

“I rolled with him for 10 minutes and he’s 61. He did a great job. He’s really friendly, a really good guy. He was cool to talk about anything we asked him.

“Renzo Gracie’s academy is a world-class level – it was a big difference between a lot of people who normally do jiu-jitsu, or they say they do jiu-jitsu. He’s tough.”

Despite only entering his first tournament at the age of 59, Bourdain won gold in the blue belt masters 5 middleweight division, at the IBJJF New York Spring Open in April 2016.

WATCH: Anthony Bourdain wins gold in his first jiu-jitsu tournament

Other than Hong Kong, Bourdain has trained in Glasgow, Maui, Istanbul, Beirut, Budapest, Kuching, Kuala Lumpur, Okinawa, Marseille and across the US.

“Both Anthony and his producer, Helen Cho, have irregular training schedules since they travel so much but they’ve been able to train at some amazing gyms all over the world,” Ho said.

“It’s definitely a great opportunity for me to train with visitors, especially high-level ones, since it tests your game against someone unfamiliar with it.

“Plus you get a chance to see new techniques and reactions. After you’ve been training with someone for a while, you get used to their games and their reactions, so it’s really nice to see how well you can do against someone foreign.”

The Hurt Locker is a stone’s throw from Chungking Mansions, where Bourdain filmed in January with the Hong Kong episode’s director, his partner Asia Argento, and cinematographer Christopher Doyle.

Chungking Mansions was also the site of Wong Kar-wai’s classic film Chungking Express, on which Hong Kong resident Doyle worked.

“To go to Chungking Mansions, this huge, frightening rabbit warren of hotels and businesses where refugees from all over the world hole up, and the site of one of Christopher’s masterworks ... I don’t think he’d been back for a long time, to return there with him with cameras and say, ‘shoot me’, I’m still pinching myself,” Bourdain told CNN.

“With everything I’ve done in my life, this is probably my professional highlight, to work with an artist that great.

“We came back with a show that looks and sounds like nothing we’ve done before. Between Asia and Christopher, we really did something special.”