Keith Duffy has said he is "heartbroken" as he announced the death of his father, Sean Duffy.
Keith said in a shared post with his son Jay Duffy: "Words cannot describe how heartbroken we are to announce the passing of our father/grandfather Sean.
"The most courageous and brave warrior we’ve ever known and probably will ever know.
"We already miss him so much."
The 47-year-old former boyband star - who currently performs as one half of duo Boyzlife with Westlife's Brian McFadden - shared a series of pictures of his late father, including one of him singing on stage.
Keith's bandmates and celebrity friends have offered him messages of support and condolence.
Boyzone's Ronan Keating commented: "Sending all our love," while Shane Lynch shared three black heart emojis.
Brian McFadden wrote: "What a fighter! What a man!"
Actor Sean McGuire said: "Oh Keith. I'm so sorry. Sending you love and strength. I'm sure you made him so proud."
And Phats & Small singer Ben Ofoedu, whose wife is Vanessa Feltz, commented: "So So sorry our thoughts and prayers are with you and the family. Vanessa and Ben."
The Irish actor and singer - who is the second of three sons to dad Sean and their mother Pat - made his name as part of globally successful boyband Boyzone, along with, Ronan Keating, Shane Lynch, Mikey Graham and Stephen Gately.
Gately tragically died aged 33 in 2009 but the remaining members of Boyzone have continued to tour and record together since.
Keith also known for playing barman Ciaran McCarthy in Corrie between 2002 and 2011.
He has appeared in reality show Celebrity Big Brother and sitcom Mrs Brown's Boys and spent the end of 2021 on the road with Boyzlife.
Keith is father to Jay, 25, and 21-year-old daughter Mia with his wife Lisa Smith who he married in 1998.
Last year Keith spoke out about what it had been like as a parent raising Mia, who was diagnosed with autism when she was a toddler.
Watch: The faces we lost in 2021