Playing music is all I ever wanted to do. In 1968, aged 17, I quit school (in Ontario, Canada) and hitchhiked all over north America, busking and staying with people I met. By 1973, I'd made it to London and I travelled around the UK with just my guitar and the clothes on my back. I got an appointment at EMI Records and was signed to make a couple of singles. But my tracks never made the Radio 1 playlist and didn't sell. After six years, I moved back to Canada, busking again and earning enough to pay my rent.

I decided that getting a celebrity to endorse me would help people to hear my music. It had to be Muhammad Ali, one of the most famous men on Earth. I had heard his fight against Sonny Liston on the radio. I saw him refuse to fight in Vietnam and be stripped of his title. He seemed to me to be a man of fibre who would give up everything for his beliefs. So I started writing to him. For a year I sent tapes and letters but got no response. Then his office told me he was in Natchez, Mississippi, making the TV movie Freedom Road. I phoned every hotel in the area until one let slip that he was staying there, so I left a message asking for him to phone me.

Half an hour later he called me back. I couldn't believe the moment had come – I had been trying him for a year. "Please don't hang up," I said. "I want to come and play you some songs. It will take me three days on a Greyhound bus, but if I make the journey, will you listen to me play?" There was silence. I thought he'd hung up. Then he said, "OK, if you come down, I'll listen."

I arrived at Ali's hotel and was taken to his trailer on the film set which was packed full of people. I said, "I'm the nut who's travelled three days to come and play you some music." He just said, "What are you waiting for?" So I took out the guitar and played my song – a six-minute philosophical track called Child Of The Wilderness. He went crazy. He was banging his fist on the table and the whole trailer shook. "This is great. This is fantastic. I've discovered me a star!"

From that point on, I went everywhere with him. I stayed in his house in Chicago. Ali would show visitors his gifts from VIPs and African royalty. I was like his court musician and performed for guests. I saw Ali do outrageously kind things just to see the look on people's faces. If he saw a mother with a buggy who looked poor, he would put money in the buggy, telling her not to tell anyone. As my mentor, the most important thing he taught me was that being kind is not just fun, it's what we are in this world to do. I co-run a charity, The Kindness Offensive, with the same ethos.

He produced my album, Muhammad Ali Introduces Michel (The First Flight Of The Gizzelda Dragon), in 1979. Ali introduces me as "the greatest singer of all time". We recorded a TV show where Ali spoke candidly about things, such as the first time he was kissed. When he introduced me on the show, holding my hand up like I was champion of the world, I had been part of his world for three years.

The album was meant to be released first in England. We had posters on the underground and radio adverts, but no one organised distribution and the album never appeared in the shops. Not a single record was sold. I went to London to try to sort it out, taking master copies of the album and TV show. But there was no reviving it. I was squatting in St John's Wood, but I didn't realise the house was due to be demolished. One day I returned and wrecking balls were banging into the walls. The tapes were lost under piles of rubble. I tried to dig through it, but I was thrown off the site.

I was too embarrassed to tell Ali. He had given me everything I'd asked for and I couldn't trouble him again. It was better for me to step back. We never spoke again. I went back to busking. But I didn't know that the lead guitarist in the backing band had taken back-up copies of the TV show and album. This year, 34 years later, he posted a video online and a friend spotted it. It was astonishing to see it. I've put the album on iTunes so people can make up their own minds. The most famous man on Earth predicted it would be a big, big hit. I'd like to be able to see him one day and tell him he was right.

• As told to Alice Grahame

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