Fleetwood said Kirwan's "love for the blues" led the guitarist to join the Grammy award-winning band, which is known for hits like Landslide and Dreams, in 1968.
Best Classic Bands will have more on the life and death of Kirwan on Saturday. Kirwan continued, stating that his legacy would live on in Fleetwood Mac's music.
In the years to follow, the band's founder, Mick Fleetwood, sought the help of the Missing Person Bureau to find Kirwan, claiming he last saw the guitarist in 1980. He died in his home city of London, according to a post on the official Fleetwood Mac Facebook page. "You will be forever missed!"
His first recorded work reached the US on the 1969 compilation album "English Rose", which included the band's chart-topping United Kingdom instrumental "Albatross" and its B side, Kirwan's composition "Jigsaw Puzzle Blues".
In a 2015 story for the New York Observer, writer and musician Tim Sommer called Kirwan "one of the great lost figures in rock history (both literally and figuratively)".
Kirwan left Fleetwood Mac in 1972 after a falling out with the other members of the band.
Image Fleetwood Mac's statement on the official Facebook page
Kirwan's work featured on the following albums: Then Play On (1969), Blues Jam at Chess (1969), Kiln House (1970), Future Games (1971) and Bare Trees (1972).
A talented singer and songwriter, Danny was recruited into the band by Mick Fleetwood as a teenager.
He remained active briefly, recording unsuccessful three solo albums for the British label DJM in 1975-79.
Kirwan was among the band members - including Fleetwood, Stevie Nicks and Lindsey Buckingham - inducted into the Rock & Roll Hall of Fame in 1998.
Kirwan was born in Brixton, South London, and his guitar skills started attracting attention at an early age.
Vettel wins in Canada to overtake Hamilton in standings
Even given the new engine Vettel had the pace of the field and managed his one-stop race untroubled to the flag. Stroll and Hartley's coming together saw the safety vehicle deployed but that was the extent of the drama.