News of Gibb's condition elicited a flood of support on social network sites and in the music community.
Peter Frampton, who like the Bee Gees rose to fame in the 1970s, wrote on Twitter, "My positive thoughts go out to Robin Gibb and all of the Gibb family. I am wishing you the best and hope for a quick recovery. Much love 2 U."
Others offering their thoughts and prayers online included Julian Lennon, the son of John Lennon, and former Jackson 5 member Jackie Jackson.
Diane Warren -- who herself has written and produced dozens of popular songs for a wide range of performers, including Aretha Franklin and Justin Bieber -- described Gibb as "one of the best songwriters of all time."