In remarks, published by People ahead of the release of his upcoming memoir, Eat a Peach, the Momofuku chef opened up about feeling like he could have done more in the years before Bourdain died by suicide at the age of 61.

"I think about the last years of Tony's life. I never asked him: 'Is everything okay, Tony? Can I do anything for you?'" Chang said. "The signs were there."

The celebrity chef, who discusses his own battle with bipolar disorder in the book, also reveals feeling as if he should have been in Bourdain’s place and that the late chef “was supposed to hold it together for all of us.”

“It wasn’t supposed to happen to him," he said. "That was supposed to happen to me. He was supposed to hold it together for all of us.

“All I know is it happened to Tony with all he had going for him. It could happen to anybody.”

This is not the first time Chang has discussed mental health following Bourdain’s death. In 2018, the 43-year-old opened up about his own struggle with depression during an episode of his podcast The Dave Chang Show, recorded two days after Bourdain’s passing.

“I thought the best way to honour Tony would be to talk about my own struggles with depression," he said. "I recorded it by myself, like two days after I found out that Tony died.

“I apologise if you're a regular on this podcast and you find this s*** too dark or too self-indulgent, but if it makes any of you feel a little bit better for seeking help for your own struggles, then it was worth it. I think it was what Tony would want me to do."

During the podcast, Chang reflected on who Bourdain was to him, explaining that he saw the Parts Unknown star as “the cool uncle, the sage, the oracle, the person that would dole out advice”.

“In many ways he's been my mentor and my North Star, because he trail-blazed a path that would not be available to me otherwise. I am in great debt to him, I miss him so much,” he said.

The chef also expressed his hope that talking about mental health issues would inspire others who were struggling to seek help.

“One of the good things is that this is going to not make talking about this kind of stuff so embarrassing and so hidden," Chang said. "The one thing I really suggest to you, if you haven’t had any help yet, or if you’re trying to find help, or if you need help, is don’t lose hope. You have to hope for a better day.”

According to Chang, who shares in his memoir an inspirational email Bourdain sent him after their meeting in April 2017, the fellow chef had always been there for him.

“He knew I was f***ing out of my mind. He knew," Chang told People. "I think the more he spent time with me, the more he realised, I can have these conversations with Chang because I need to help him."

Samaritans is available 24/7 every day of the year to listen and offers support to anyone who is struggling to cope. Contact Samaritans by phone, free of charge, on 116123, or visit samaritans.org to find details of local branches.

If you are based in the USA, and you or someone you know needs mental health assistance right now, call National Suicide Prevention Helpline on 1-800-273-TALK (8255). The Helpline is a free, confidential crisis hotline that is available to everyone 24 hours a day, seven days a week.