Irish broadcaster Gay Byrne has died at the age of 85 after a long illness, RTE said.
The RTE broadcaster and former Late Late Show host had been undergoing treatment for cancer.
The father-of-two died in Howth surrounded by his family.
RTE director-general Dee Forbes paid tribute to Mr Byrne.
“We are all greatly saddened by the passing of Gay Byrne who has been a household name in this country for so many years,” she said.
“Gay was an exceptional broadcaster whose unique and ground-breaking style contributed so much to the development of radio and television in this country.
“Gay’s journalistic legacy is as colossal as the man himself – he not only defined generations, but he deftly arbitrated the growth and development of a nation.
“Ireland grew up under Gay Byrne and we will never see his like again. My deepest sympathies to Kathleen and his family.”
Gay Byrne, a great friend, colleague and broadcasting legend. pic.twitter.com/HDSRK1lS2R
— RTÉ Radio 1 (@RTERadio1) November 4, 2019
Born in Dublin in August 1934, Gay grew up on the South Circular Road.
He started work as a newsreader and continuity announcer on Radio Eireann in the late 1950s before moving to Granada Television in Manchester, where he worked on a variety of shows, interviewing acts including The Beatles.
For a time he commuted between Dublin and UK, working for both the BBC and RTE, but came back to Ireland full-time in the late 1960s as presenter and producer of The Late Late Show.
The programme went on to become the world’s longest-running chat show.
He also presented a long-running radio show on RTE Radio 1, first known as The Gay Byrne Hour and then The Gay Byrne Show.
The show had a close relationship with its listeners, many of whom wrote to or phoned Gay to comment on the issues of the day, and with their own stories.
He won a Jacob’s Award for the programme in 1976.
Over his long career Gay presented The Rose of Tralee, The Calor Housewife of the Year competition, as well as a range of special programmes.
He presented his final daily radio show in 1998 and his final Late Late Show the following summer.
However, he did not retire from public life, becoming the chairman of the Road Safety Authority and presenting other acclaimed television shows, including The Meaning of Life.
He is survived by his wife Kathleen, their daughters Crona and Suzy, and their families.
Gay Byrne was the most influential broadcaster in the history of the State, a much-loved figure who changed Ireland for the better in so many ways. I knew him when he was Chairman of @RSAIreland and saw the effectiveness of his campaign against the needless tragedy of road deaths
— Leo Varadkar (@LeoVaradkar) November 4, 2019
Mr Byrne was described as a man “of great charisma” by Ireland’s president Michael D Higgins.
Mr Higgins added: “Gay Byrne was someone who exuded warmth and presence, who was possessed of effortless wit, charm and who had a flair for broadcasting.
“This was combined with an innate gentleness as a person, professionalism and humour.
“Through his work in radio and on television he challenged Irish society, and shone a light not only on the bright but also the dark sides of Irish life.
“In doing so, he became one of the most familiar and distinctive voices of our times, helping shape our conscience, our self-image, and our idea of who we might be.
“Beyond compassion, which he had in abundance, he had a sense of what was just.”
Broadcaster Ryan Tubridy was among those who paid tribute to Mr Byrne.
“It is with enormous and profound sadness that I heard of the passing of my friend and mentor, Gay Byrne,” he added.
“He was the master, a once-off and the likes of which we will never see again.
“I watched him as a child, worked alongside him as a young man and he guided me as I grew older, and I will forever be indebted to him.
“We in RTE have lost a friend, a family have lost a father and a husband and the country has lost an icon.”
Fianna Fail Leader Micheal Martin said: “Gay Byrne has left an indelible mark, not only on Irish broadcasting, but on Irish society as a whole.
“Through his radio programme and TV shows, including his 37 years as host of The Late Late Show, Gay was a feature in Irish homes the length and breadth of the country.
“His intellect and emotional intelligence was unparalleled and his ability to sensitively approach delicate and sometimes controversial issues set him apart from other presenters.
“Gay Byrne was a rare treasure who touched the lives, not only of his family and friends, but the hundreds of thousands of people who welcomed him into their lives and their homes on the radio and TV.”