Last time he was in St Albans, Irish comedian Jason Byrne remembers energetically bouncing down the aisle on a space hopper. But when he arrives back in the city this month he’s more likely to be limping on stage complaining about needing a knee replacement after completing the New York Marathon.

“I literally thought I was going to die,” states the Dubliner, “because my heart and lungs and everything were perfect but my legs were mangled so I thought it was only a matter of time before I had a seizure. But luckily I didn’t,” he says in a unnervingly serious voice.

His sombre tone throws me off momentarily as the 42-year-old had opened our chat with a surreal story about his latest voiceover job for Sky programme Wild Things: “It’s like It’s A Knockout with a couple who go into a forest and one is dressed like an animal and they can’t see what they are doing and their partner has to tell them which way to go.

“The last voices I did were an owl, a squirrel and a badger all in a circle trying to hit a fruit with a baseball bat and all they were doing was hitting each other in the head.”

“Seriously?” I ask.

“Yeah, I know.”

This is quickly followed by Jason describing dressing up as a sperm with Sarah Millican, Phil Jupitus and Des Bishop for his Irish chat show Snaptastic.

“The TV show is like Graham Norton and Don’t Forget Your Toothbrush mixed together. Celebs bring in photos of themselves as kids and then I interview them. And at the end we recreate a photo, so there we were with these white caps on with tails trying to push into this egg. It was f***ing hilarious.”

In fact Jason jokes his way through most of the interview with easy charm, but it is clear that underneath he is a man who relishes a challenge, training for what was his first ever marathon in between his chat show appearances and starting his latest tour.

“You see what I’m trying to do is slowly kill myself,” teases the comedian, who was born in Ballinteer.

“I didn’t think I was going to be able to finish. At 22 miles I got vicious cramps in my legs and had to get people to massage them to get them going again and then hobbled the rest of the four miles. I have probably damaged myself a bit in my knee but there was no way I wasn’t going to finish as I was doing it for a children’s charity in Dublin.”

So was the Edinburgh Fringe regular able to laugh his way through the pain?

“F**k no. Someone foolishly said to me afterwards ‘tell us a joke’ and I was like ‘get away from me, I’ll f***ing stab you.”

The smile returns to his voice as the father-of -two adds: “The last image I have of it was me in a bath, my wife had to help me into the bath in the hotel room while she washed my hair and fed me chocolate while I slowly weeped.”

You might get the chance to hear more about his ordeal when he comes to The Alban Arena with his latest, ever-changing stand-up routine entitled You Name the Show. Not only does he have a big wheel of topics to spin and pick from on the night, with the marathon now firmly added, but he will also be asking the audience to come up with titles for the show. The best one at the end of the tour gets £500, not cinema vouchers as Jason originally suggested.

“Most of them have bad language in and are very obscure,” he reveals. “In Leeds it was something like Share the Maltesers You Fat B*****d, Auntie May Wants Some.”

Jason says the marathon was without a doubt the hardest “but greatest thing” he has ever done, and there are similarities with running and doing a comedy gig as the nerves start to build before both. But he says he will be returning to running and will keep getting back on stage as “it’s his job”.

“It’s like saying to anyone “why do you go to work?” You just have to do it. This is the career I chose. I’m 42. I can’t just go ‘ah I’ll try something else’. So that’s it. Once I’m on the stage I’m fine.

“I have got an amazing drive and great will power and a strong mind. I’m very much a shut up and stop f***ing moaning, person.”

Alban Arena, Civic Centre, St Albans, Thursday, November 27, 8pm. Details: 01727 844488,