Kielty was speaking in his opening monologue on the return of The Late Late Show on RTÉ One after the summer break.
In July, Kielty and his wife Cat Deeley, who presents This Morning on ITV alongside Ben Shephard, announced their separation after 13 years of marriage.
The pair, who have two sons together, made the announcement in a statement issued on July 29.
Patrick Kielty and Cat Deeley.
Today’s News in 90 Seconds, Friday, September 12
During his monologue at the beginning of the show, Kielty said “it is so nice” to be back in the host’s chair, “especially after this summer”.
“I’ve genuinely been blown away by all the love and support that you guys have sent my way,” he said.
“One of the greatest joys of hosting this show is that you’re never alone. And so, to all of you who have been so kind to me and my family this past few months, can I just say a huge go raibh míle maith agat,” a visibly emotional Kielty said.
“It’s one of the many reasons why walking out here is always a privilege, why being back here with you tonight truly puts flesh on my bones, and why it never gets old to say these words – welcome to The Late Late Show.”
In the late night chat show’s return for its third season with Kielty at the helm, guests included Hollywood stars Colin Farrell and Margot Robbie.
The pair were on to discuss their new film A Big Bold Beautiful Journey, a romantic fantasy about two strangers, played by Farrell and Robbie, and their “unimaginable journey” together.
During the interview, Farrell reflected on his unsuccessful audition to be a member of Boyzone.
“I sang Careless Whisper twice, and the second time was because they couldn’t believe how bad the first time was,” he said.
“They were like, ‘Could you do that again please?’”
When Robbie said she was unaware of who Louis Walsh was, Kielty added that she was aged just three when Boyzone was formed.
“I was on an Irish newspaper with the rest of the band, like it was all happening and then I got a call saying ‘Sorry man, you’re tone deaf’
“But thank God, then I wouldn’t be sitting here with you having done this and talking to Patrick.Sliding doors.”