Published Tuesday, 22 May 2012
Gibb lost his battle with cancer on Sunday, and Keating, who was flying to Europe from Australia when the news broke, has reached out to the sole surviving member of the trio, Barry Gibb, as he mourns his brother - nine years after third member Maurice Gibb died.
Speaking on morning show Daybreak, the Irish star says: "I couldn't believe it. I flew in from Sydney yesterday morning as I was on a plane for most of the day and when I landed in Heathrow I got the word about Robin.
"My thoughts and prayers are with his family, his brother Barry who's been through so much, my God - to lose all your brothers like that, it's just devastating."
Boyzone covered the Bee Gees track Words and the two groups teamed up to perform the song in the mid-1990s - and Keating has fond memories of their time together.
He adds: "We were lucky enough to work with him, to sing with him, perform a song called Words together and they really took us under their wing and they were great to Boyzone, so we're thinking about all the family."