The late rock star's family have shared a heartfelt message on Twitter announcing the death of their loved one.
In the statement, they described him as an "extraordinary man with an extraordinary heart".
"He brought so much love and kindness to everyone he met, and he leaves a huge hole in our family," they added.
"He would humbly say he was 'just a plumber from Edinburgh who got lucky'.
"However we were the lucky ones; the ones that were lucky enough to have Alan as part of our lives."
The Bay City Rollers (including Alan's brother Derek, Les Mckeown, Stuart 'Woody' Wood, and Eric Faulkner), rose to fame as a teen band in the 1970s with their biggest hits Bye Bye Baby and Shang-a-Lang finding success all over Australia, The UK and USA.
A number of tributes have been made on Twitter after the sad news of the rock star's shock death.
Sending love to Alan's family during this difficult time.