You hardly need to be told that John Bishop is good chat. That is, after all, how the Liverpudlian has earned his living for 20 years or so. His stand-up comedy – now filling arenas – has the quality of a careering monologue delivered to a party of eager pals. It is confessional. It is uninhibited. It is often outrageous.

Chiselled and matey, Bishop, meeting me in one of Dublin’s grandest hotels, needs no encouragement to launch into his flow. I assume he knows the city well. No, not just because we regard all Liverpudlians as honorary Irish folk. Back in the mid-noughties he was a regular on the RTÉ TV show The Panel. That was a leg up for a comedian still juggling his ambitions.

“Oh yeah, The Panel was the second thing I ever did on telly,” he says. “And it was the first one where I became a regular. I’d be coming over here on a Sunday. We used to film it on a Sunday, and then I’d be going back to work on Monday morning.”

He was still working in marketing for a pharmaceutical company?

“Yeah, I was still doing the day job.”

The story of how Bishop moved from the workaday grind to comedy celebrity is an extraordinary one. Indeed, it was sufficiently interesting to inspire a fine new film by Bradley Cooper. Is This Thing On? stars Will Arnett as Alex, a middle-aged New Yorker who, by chance rather than design, blunders into the world of stand-up comedy. Laura Dern plays his initially long-suffering wife. Ciarán Hinds is his weary dad.

It is one of those semi-true stories whose most unlikely moments – diversions you wouldn’t dare make up – turn out to be based closely on the facts. Arnett’s character, then breaking up with his wife, signs up for an open-mic night at a comedy club as a way of avoiding the cover charge. Months later his wife wanders into the venue with pals and reels backwards when she sees the man she is divorcing up on stage. More bizarre still, he is doing material based on their stuttering relationship.

This is pretty much what happened to Bishop and his wife, Melanie.

“Yeah, that’s the Hollywood moment in the film,” Bishop says with a laugh. “I’d started doing stand-up comedy and hadn’t told anyone about it. We were properly split up. We were split up nearly two years at this point. And I got a phone call to go to the Frog & Bucket – much like Alex in the movie. ‘Somebody’s dropped out. You’ve got a chance to do a paid set.’”

Melanie, arriving for a night out with her pals, had no idea Bishop had taken up comedy as a hobby.

“The people she was with couldn’t understand why she went ‘What the hell?’ when I walk on. I end up telling jokes about her, and then I see her. In the film Alex doesn’t see her. But I caught the eye of her. I remember because I told this joke about killing her and cutting her head off. Not the best joke ever. And I remember thinking, That’s going to cost me another £10,000 in the divorce!”

Quite the reverse happened. Melanie approached Bishop after the set and, according to a recent interview, told him “she had just encountered the funny 21-year-old Manchester Poly student she had first met and fallen for”. He had become his true self again. It involves only a little hyperbole to argue that his shift into joke-telling reanimated their marriage.

“I was a relatively young dad,” he says. “We had our first kid when I was 27. We had three by the time I was 31. I didn’t come from a wealthy background. So I was really driven to try and do well.

“And I’d become that person who comes home from work, gets on the mobile phone, pats the kids on the head, pecks the wife on the cheek and then goes upstairs to the home office.

“I’d lost the little glint in my eye. I’d lost that sense of adventure. Everything was all about the security. And so when I found stand-up comedy, I found myself again.”

Will Arnett and Laura Dern in Is This Thing On? Photograph: Jason McDonald/Searchlight PicturesWill Arnett and Laura Dern in Is This Thing On? Photograph: Jason McDonald/Searchlight Pictures

Bishop was born in Liverpool 59 years ago and raised in the nearby Cheshire towns of Runcorn and Winsford. As he says, it was no sort of privileged background. When he was six, his dad, a labourer, was sent to prison after getting in a fight defending the boy’s mother. “Even the arresting officers said the case should have been thrown out,” he told the Daily Mirror in 2014.

After school Bishop studied English for a while in Newcastle before taking a BA in social science at Manchester Polytechnic.

He cites Tom O’Connor, the great Liverpudlian comic, as an early influence.

“I remember my dad working at British Leyland, the car factory, and coming home with this tape and playing it in the kitchen,” Bishop says. “I thought, Why is he playing a tape? It’s just someone talking. There’s no music. It was Tom O’Connor, who had been a schoolteacher in Liverpool. And that was my first introduction to somebody just telling stories – mum and dad, sitting in the kitchen laughing. It was great.”

Liverpool has a great comedy tradition, of course. Jimmy Tarbuck was unavoidable on 1970s TV. Paul O’Grady is much missed. Ken Dodd, the late, unclassifiable gag-machine oddball, remains a legend in the city.

Will Arnett in Is This Thing On? Photograph: Jason McDonald/Searchlight PicturesWill Arnett in Is This Thing On? Photograph: Jason McDonald/Searchlight Pictures

“I remember meeting Ken Dodd at a dinner,” Bishop says. “I got asked to present an award to him. And we sort of kept in touch. He was phenomenal. Ciarán Hinds’s agent is a guy called Simon. He used to be Ken Dodd’s agent. So, on Monday night, we had the dinner with the crew, and it was lovely. I’m sat opposite Ciarán Hinds’s agent. We got talking. I could have talked about anything. But we just talked about Ken Dodd.”

Is This Thing On? is no tale of overnight success. Alex has just about got himself noticed by the end of the film. That is how it was for Bishop. Rather than any sudden jolt into celebrity, he remembers a slow, gradual ascent. Was there a single incident that persuaded him to give up the day job?

“I knew I was getting good at it, and I’d started to get the odd after-dinner thing, which was better paid than doing a comedy club,” he says. “But the big, pivotal thing for me – the straw that broke the donkey’s back, as it were – was Liverpool getting into the final of the Champions League in 2005.

“I had a ticket, but I couldn’t go, because I had to attend a conference in Seattle. I had to attend the international immunology and transplantation conference. I had a ticket for the final, and I had to give my ticket up because my boss said, ‘Look, this is your job.’”

He managed to get back to England in time for kick-off, but there was no way he could make it to the match, in Istanbul. Liverpool famously beat AC Milan on penalties.

“I went into this mad depression for months because I realised that I was a man who was being told what to do by another man,” he says. “I suddenly thought, I’ve got this thing, this stand-up comedy, and I appear to have an ability at it. I appear to have a skill at it.

“I have odd things, like doing The Panel, but I wasn’t taking the lead, because my job was too good. I realised, I’m not doing it because I’m married with kids and a mortgage. And if I don’t do it I’m going to end up blaming them down the line.

“That would be a coward’s way out. For the first three years I just kept increasing the mortgage. Then I turned the corner.”

John Bishop 25 Tour: Live from Dublin. Photograph: Deirdre Brennan/Sky UKJohn Bishop 25 Tour: Live from Dublin. Photograph: Deirdre Brennan/Sky UK

So he didn’t walk straight into fame and glory?

“No, I did my first gig a month away from being 34. I left my job when I was 40. And I got my breakthrough on telly maybe two years after that.”

Bishop still mines his personal life for the ambling yarns that make up his often emotionally raw act. The story of his getting back with Melanie continues to generate laughs and a few sympathetic sobs. In 2022 he made a documentary – entitled, with characteristically cheeky humour, John and Joe Bishop: Life After Deaf – that dealt with the eldest of his three sons losing much of his hearing following an illness.

This is a tricky business. Has he set limits as to places he won’t go in excavating his family’s private life? Have there been any fallings-out?

“It’s odd, that. You do a little bit of self-editing, because there has to be some kind of universality to it,” he says. “If you tell something that nobody else can relate to, then how is that going to be humorous? Or if you’re talking about something that doesn’t end in warmth or positivity?

“I’d like to think, when I do talk about those things, everyone can see that it’s basically about love. But sometimes I just let it come out and wait to get told off! It’s easier to apologise than ask permission.”

When Bishop did finally hit big he just kept hitting. The first time I saw him in the flesh, he was striding up the red carpet at Cannes film festival for the premiere of Route Irish, Ken Loach’s political thriller from 2010. He played an unlikely companion – a Liverpool FC supporter, of course – to Jodie Whittaker’s 13th incarnation of the Doctor in Doctor Who. It is an English national treasure indeed who gets a credit with Loach and the indestructible time lord.

Many people who become famous in middle age express themselves grateful they got the chance to mature before the paparazzi began circling. Still, it must be difficult for family. One day Dad is unnoticed in Tesco. The next he is on Graham Norton.

“I did a podcast called Parenting Hell the other day with Josh Widdicombe and Rob Beckett – comedians but also parents of young kids,” he says. “The difference for them is they’ll always be comedians in their kids’ eyes. They will always be well known.

“It wasn’t like that for me. All of a sudden, from just being a dad, I was getting stopped for photos by people the same age as them. I probably didn’t understand what that must have been like for them. We talk a bit about it now, and I’ve learned a lot more.”

Is This Thing On?, set in far-off New York, allowed the younger Bishops some distance.

“My family is strong enough to see it and enjoy it rather than see it and think, Oh, God, is this about me as teenage boys? So sometimes the stars align.”

Is This Thing On? is in cinemas now