The 56-year-old comedian and actor told The Guardian, that the incident was one of the most embarrassing things to happen to him.
Explaining his faux pas, in a tale that could be mistaken as a storyline for his character Dougal Maguire he said: “My girlfriend’s mother passed away when I was 17 and I went to what I thought was her funeral.”
“I was standing there in my best, shiniest suit and realised everyone was looking at me. There were two funerals in town that day and I went to the wrong one.”
During the interview, he also revealed his biggest fear is being laughed at.
“[It’s] terrible for someone who makes a living out of making people laugh,” he explained.
The actor and comedian recently revealed to the Sunday Telegraph that he was paid just £2,000 per episode of Father Ted.
Making a total of £50,000 for appearing in all 25 episodes of the Channel 4 show.
“To put it in context, I remember hearing that a senior figure in a sitcom was doing a Christmas special for £45,000 per episode,” he told the publication.
“I was fine with that. I wasn’t in it for the money.”
O’Hanlon has recently released his second novel ‘Brouhaha’.
Published by HarperCollins, the dark comedy follows the explosive aftermath of the death of Dove Connolly in the town of Tullyanna.
"I'm terrified. I'm proud of it but you never know how it's going to be received," he told Sunday World.
"It's about a person who disappeared three years previously and what happened to them and why. It's kind of a detective novel and a regular novel about a small town, that's satirical and also dark and grim."
"When the pandemic started, I had a two-year hiatus and I had the skeleton of this which I'd written six or seven years ago."
"I didn't kill myself, we still had cocktail hour at three o'clock every day, but I think I would have gone nuts if I didn't have this to do."