STANDING at a church altar, the Gleeson brothers find themselves in character, contorted into a peculiar kind of stranglehold which also involves fingers in mouths, two MMA enthusiasts and a guitar.

It's a peculiar set-up to be sure.

And yet it is, in many ways, one that perfectly captures the physical, somewhat slapstick nature of the duo's latest black comedy, Frank Of Ireland, which will air on Channel 4.

Written by Peaky Blinders actor Brian Gleeson and his brother, Ex Machina and About Time star Domhnall Gleeson, alongside Your Bad Self creator Michael Moloney, Frank Of Ireland is a curious blend of physical comedy underpinned by delightfully dark humour.

"It is a physical, slapstick and ... we were talking references earlier - if you grew up watching Jim Carrey in Dumb And Dumber, I think that element of it is important to us and is definitely there," says Brian, 33.

"But I suppose it's a kind of a classic sitcom format, really, but you know, structured with an Irish sensibility, I suppose."

As the name would suggest, Frank Of Ireland centres around Irish 32-year-old "manchild" Frank, who still lives at home with his parents in Dublin - a failed musician, narcissist and fantasist, played by Brian.

It's a prime example of arrested development.

According to his brother and co-writer Domhnall, 37, the character of Frank can only be described as a "kind of 13-year-old personality that's never grown up because he's too comfortable in life and has a temper and expects the world to do him favours".

"And then we have Doofus," continues Domhnall with a grin, "who is more like a nine-year-old, who's younger and looks up to Frank and [is] more naive and more stupid and doesn't know as much.

"He's younger. He's very innocent..."

Depicting the at-times co-dependent relationship of the on-screen brothers, the series follows the unconventional pair as they face all manner of misadventures in the wake of Frank's ex-girlfriend moving on with a new partner.

"It's almost like, in a lot of ways, I remind myself of Ryan Gosling," laughs Domhnall with a grin.

"There's this thing that Ryan Gosling had in the film The Place Beyond The Pines. He has a tattoo of a tear on his face or something like that.

"And apparently, he decided that maybe [his] character should have that. They did a make-up test and he saw it and he said to the director, 'I absolutely do not want to have it there; it looks really stupid'.

"And the director said, 'No, if the character had that done, he would think it was cool and then he would have to live with it for the rest of his life. So that's what you're going to have to do. You're going to have to just make a part of your character that you regret'.

"And I think with Doofus, there's a similar thing with the name. It was funny early on, then I thought, 'What the hell are we doing? I don't want to play a character called Doofus - that's insane!'

"And then I guess it just became part of who he was."

Normal People actress Sarah Greene plays Frank's ex-girlfriend Aine, who becomes something of an obsession for Frank, who hasn't written or played a song in seven years and five months - the precise length of time since their break-up.

However, that's merely a coincidence, as Frank assures anyone who will listen.

Desperate to win her affections once again (if only out of pure jealousy), he embarks on a mission to compete against her new lover, which marks the start of the pair's journey down a long and comical road.

"I think it's funny, even when you hear the word sitcom, a certain thing comes into your head which isn't necessarily exactly what this is," continues Domhnall.

"Because elements of this show feel more like the real world and feel like real relationships. It's not all just people slipping on banana skins."

Frank Of Ireland had long been something of a passion for the Gleeson brothers.

A production years in the making, the series was brought to life with the help of Catastrophe star Sharon Horgan and producer Clelia Mountford's company, Merman, prior to being commissioned.

"It was new for us, this format, and even getting this far with a project, it was kind of crazy," says Brian.

"And then Channel 4 got involved.

"I think they helped us through that whole process because there was this idea that it could be stylistically different.

"We didn't really want it to be that but Channel 4 thought it would be a good idea just to shoot a promo, like a 12-minute promo with a few scenes put together, just to find the tone of the world.

"And I think that was really important - both for the look of the show and the feel of the show."

It's a sentiment shared by Domhnall, who says the final project was very much shaped by the initial teaser.

"He sounded a certain way and in my head, he sounded a certain way in Brian's head, it sounded a certain way in Michael's head," continues Domhnall.

"And when Brian took it and ran with it in that taster, it was amazing, because you go 'Oh, I see!'.

"It really centred the writing process."

Frank Of Ireland arrives on Channel 4 on Thursday April 15.