Now the guitarist in the pop group's early line-up of the 1960s, latterly homeless on the streets of London, may be reunited with former colleagues.
Mr Kirwan, 42, was traced by the Missing Persons Bureau and the Independent after Mick Fleetwood, the band's founder, heard about his plight. Mr Kirwan has been living in St Mungo's Hostel for homeless people in the West End of London for the past four years. He left the band before their success with Rumours, the album that sold 40 million copies in the late 1970s.
Since then he has been living on social security and 'dribs and drabs' of royalties from the band's early days. Yesterday, looking cheerful but dishevelled, he told of constant travels with a rucksack and of five years living as a hermit in a dark basement flat in Brixton, south London.
However, he said he felt no bitterness: 'I've been through a bit of a rough patch but I'm not too bad. I get by and I suppose I am homeless, but then I've never really had a home since our early days on tour. I couldn't handle it all mentally and I had to get out. I can't settle.'
Mr Fleetwood contacted the Missing Persons Bureau in London via the Los Angeles correspondent of a show business news agency. In this week's edition of the Big Issue, the London magazine sold to help the homeless, he said he last saw Mr Kirwan in 1980.
'While we were in London, I got Danny's number and in due course he showed up at the hotel,' he said. 'He appeared looking grubby. It was heartbreaking. He'd slept on a park bench the night before.'
But Mr Kirwan appeared in good spirits yesterday at the Coach and Horses, his favourite pub in the West End. He spoke of the traumas of touring but also of the pleasures: 'I was lucky to have played for the band at all. I just started off following them around, but I could play the guitar a bit and Mick felt sorry for me and put me in. I did it for about four years, to about 1972, but . . . I couldn't handle the lifestyle and the women and the travelling.'
He was not the only band member so affected. Peter Green, lead guitarist and co- founder, left the band and gave his money to charity, saying drugs and guilt made him quit.
Mr Kirwan said: 'If Mick would like to see me, then that would be nice. But he would have to come over here. America terrifies me. If he can't come, then that's OK. I don't really need anything. Unless he fancies popping a million pounds in the post. . .'