It broke my heart when Tony died. I loved so much about him. His obvious love for life and for people. His balls-out willingness to do whatever was put in front of him. He was ultra-charismatic on television, in his writing, and in person, but totally down to earth with everybody he met. I was a fan for years before we became friends. He seemed like someone who would be great to hang out with. And so it turned out.

I first came across Tony watching his shows on the Travel Channel [No Reservations and The Layover]. Then I got Kitchen Confidential [his 2000 bestseller about working in New York kitchens] and just loved it. A few years later, he got to know Queens of the Stone Age, but I had left the band as a full-time member by that point. The guys had heard he was in town, invited him to a show, and they just hit it off. He had such a great sense of humour. He got them to play Christmas songs in Christmas jumpers on his show. After that, Josh [Homme, Queens of the Stone Age frontman] introduced Tony to my music. He got into it pretty heavily, which I heard about. I found it unbelievably gratifying.

Then he asked me and Josh to write the theme to his new show, Parts Unknown, in 2013. The first time we had contact was over the phone: he was so warm and so funny. As he was describing the general vibe of what he wanted – “Mark, I want it to be like Joey Ramone doing What a Wonderful World!”– I was already writing it in my head. I’d thought it would be a really difficult thing to do, but because of Tony, it was easy.

We had a very strong friendship for three years or so over email before we met, but it felt like longer. He was always travelling making his shows, and I was travelling with music. He became a great mentor to me, and a champion of my work. Take when I had to write a preface to a book of lyrics I was putting together [2017’s I Am the Wolf]. I was a bit unsure of doing it – I had never done anything like that. But he was super-excited when he read what I’d done, and kept encouraging me to write an actual book. I had never wanted to do that – it seemed like climbing Everest to me – but I was swept up by his enthusiasm, so I started one. I’d send chapters to him before my editor, and he’d reply with comments and suggestions. That was the kind of person he was – always giving, always wanting to support people.

Anthony Bourdain in Sydney, 2005. Photograph: Fairfax Media via Getty Images

But I had no idea what lay behind all of that. Yesterday, I watched the Seattle episode of Parts Unknown for the first time. Recording that was the first time we met. And there’s this final shot of him sitting at the bar, listening to one of my songs… In retrospect, you can see the pain written all over his face. It never occurred to me that somebody like him could be unhappy. But I’ve been thinking about being someone like that, who travels so much… I know how difficult it is, and how lonely it can be.