O'Hanlon first shot to fame playing the dim-witted Father Dougal on 'Father Ted', after he was spotted by the producers, performing on Dublin's stand-up comedy circuit.
"I'm not really Irish," O'Hanlon jokes (he is from County Monaghan). "I've just realised they've done so well on TV in recent years that I've adopted an Irish persona. It worked for Graham Norton - he's actually French!"
But seriously (if that's possible), does O'Hanlon ever get concerned that he's gained a profile for playing dim-witted characters, like Dougal and Thermoman?
"I think that I've still got no choice really but to play idiots. I think it's what I was put on this planet to do," he says. "I really enjoy playing fools. I don't know if this is good or bad, but it seems to come easily to me.
"It's amazing the number of people who ask my wife, 'Is he really that stupid?' She doesn't know whether to laugh or cry! She doesn't really defend me though. We have a very weird relationship. I think she enjoys my humiliation."
O'Hanlon's biggest challenges on the set of My Hero come from his Thermoman costume, which used to take half an hour to get on. "By the third series, we had it down to about three minutes," O'Hanlon says. "The costume comes in two parts - a muscle suit under the lycra, which is something I'm ashamed to admit!"
Thermoman also wears a black visor that O'Hanlon can't see through ("I have all my lines printed on the inside of the visor," he jokes), which can make moving around a hazard.
"I'm pulled along on a little trolley in the directions in which I have to go, but there was an accident once where I ran into a door three times in a row!"