Gerry Ryan was found dead at his Dublin home
Hundreds of people have visited RTE's radio centre in Dublin to sign a book of condolence for the late broadcaster Gerry Ryan.
The 53-year-old radio and television presenter was found dead at his Leeson Street apartment in the capital on Friday.
Irish Police said there were no suspicious circumstances surrounding his death.
U2's lead singer Bono was among those who paid tribute.
Mr Ryan, who was from Clontarf in Dublin, had been broadcasting on RTE 2fm for over two decades. He also presented on TV.
RTE issued a statement on behalf of Mr Ryan's wife Morah, from whom he was estranged, and his five children.
It said they were in shock and were requesting privacy.
RTE radio managing editor Claire Duignan said that Mr Ryan had complained of being unwell on Thursday night and had told colleagues he did not think he would be able to do his show on Friday.
She added: "When he spoke with people to say he would not be in today, they obviously expressed concern and asked whether he needed a doctor. But he said not, he was fine, but he wouldn't be in today".
The Irish prime minister, Brian Cowen, said he was "deeply saddened" by the death of "one of the greats of modern Irish broadcasting on radio and television".
He added: "As a broadcaster, Gerry Ryan was both informed and intelligent, forthright and articulate.
"As a man, he was generous, famously irreverent and witty.
"I had had the pleasure of meeting him many times, both in front of and away from the microphone. He was always engaging company and a man of considerable charm."
Irish President Mary McAleese called Mr Ryan "extraordinarily talented".
"His unique communication skills and larger than life persona entertained and enlivened a national audience over many years", she added.
"His untimely death will be widely mourned, by his fellow colleagues at RTE and his many fans, but most especially by his family and friends who are in my thoughts and prayers."
Fellow RTE broadcaster and long-time friend Joe Duffy choked back tears live on air as he recalled the "bold schoolboy" he first met in 1979 at Trinity College, Dublin.
"He was the best company you could ever have," he said.
"He was bold in every sense of the meaning of that word. He was brave in his broadcasting; he was brave in his life; he lived his life to the full.
"He was bold in the sense of being cheeky, bold in the sense of being arrogant, bold in the sense that you loved hanging around with the bold schoolboy in your class."
RTE director general Cathal Goan said the broadcaster was "struggling to cope with inexpressible grief".
He added: "We have lost a broadcasting colleague whose presence, voice and work defined a broadcasting genre in Ireland and defined a generation.
"Those who had the privilege of working with him will have a sense of bewilderment at the suddenness of his leaving us, and an abiding affection for a broadcaster who was a one-off."
The Independent Broadcasters of Ireland, the body representing the country's independent commercial broadcasters, also offered its condolences.
A statement said: "A great voice has been lost to Irish radio and the entire industry is deeply saddened to lose one of Ireland's most professional broadcasters."