As co-creator of British sitcoms Catastrophe and Motherland as well as Divorce, the high-profile HBO series marking Sarah Jessica Parker’s first major role since Sex and the City ended in 2004, Sharon Horgan has earned a rest.

The indefatigable Irish writer-actor-producer’s latest project, Game Night, is a madcap comedy starring a tantalising ensemble comprised of Rachel McAdams, Jason Bateman, Kyle Chandler and Jesse Plemons, putting Horgan into a place viewers haven’t seen her for a while: in front of the camera reciting lines written by someone else (namely Mark Perez). Directed by Jonathan Goldstein and John Francis Daley (who played Sam Weir in Freaks and Geeks), the film follows a group of friends whose weekly couples game night turns into a real-life murder mystery.

With a two-month break lined up, Horgan – rather than switch off until the next contractual obligation – threw herself into the role of Billy Magnussen’s Irish girlfriend Sarah as a whirlwind reward after a busy year of writing.

“I don’t get to do that much else because writing shows takes up a bunch of time,” she told The Independent during the UK leg of the film’s hectic junket cycle. “I had two months where I could do something and just wanted to do a bit of acting because I’d spent the year before doing Divorce and [then] went straight into Motherland. I just felt like I wanted to escape from writing for a bit and do something that was fun.”

The film saw Horgan swap Catastrophe’s cosy east London locales for the streets of Atlanta, which she describes as “a nice place to hang out”.

“That’s one of the nice things about the job – you end up in places you don’t know you would have had it not taken you there.”

Horgan and Billy Magnussen star in the new comedy film ‘Game Night’ about a group of friends whose weekly couples game night turns into a murder mystery (Warner Bros) (Warner Bros. Pictures)

Horgan’s schedule is best described in one word: busy. One of the leading female writers in comedy, her breakthrough arrived with BBC3 series Pulling,whose short life (it was cancelled after just two series) belied its critical acclaim and cult status. Horgan co-wrote the series alongside Utopia creator Dennis Kelly, with whom she’s currently developing one of two anthology-style shows.

Then there’s the small case of writing both Catastrophe and Divorce – which she’s steered to success on both sides of the pond – and lending her voice talent to animated Netflix series BoJack Horseman. With most showrunners fortunate to have one successful show, Horgan now has several to her name. When it comes to developing new shows, is it just a case of diving in and seeing what lands?

“Yeah, a lot of times it is,” she levels. “There have been a few things I’ve started writing that didn’t have a commission to get them going which became things. I just thought, ‘Let’s do this.’ Writing takes a long time and it’s pretty hard so you have to really enjoy what you’re doing – you’ve really got to have something to say to make it work. So generally, if I want to talk about something, that’s the thing I’ll end up writing. Sometimes you get lucky, sometimes it sits in your drawer – but yeah, I guess there is an element of: ‘F*** it, let’s just do it.“

Horgan is quick to humbly attribute the success of her projects to the actors she feels lucky to have read her lines, a list that makes for eye-opening reading: Molly Shannon, Tracy Letts, Ashley Jensen, Mark Bonnar and, of course, the late Carrie Fisher. She also wrote Divorce‘s lead role of Frances Dufresne specifically for Parker. One recent series she believes would have fallen short of the mark had they not assembled the right cast is London-set sitcom Motherland, which follows the travails of middle-class mothers played by Anna Maxwell Martin, Lucy Punch and Diane Morgan.

“We just got really lucky with those girls,” Horgan tells me, “and with Paul [Ready]. I don’t think it would have been the show it turned out to be had we not. It’s not about doing justice to my words, it’s about finding the person who just can make your words better, honest to God – that happens all the time; you write something and it’s sort of an OK scene and then you see them do it and you’re like, ‘Bloody hell, that’s really good.’ That’s what it’s about.”

BBC series ‘Motherland’, co-written by Horgan: ‘We got lucky with the cast,’ she says (BBC/Delightful Industries/Merman/Colin Hutton)

It’s similarly hard to imagine Catastrophe without Horgan in the lead role. She plays Sharon opposite Rob Delaney’s Rob, a duo whose weekend of non-stop sex results in pregnancy. The series debuted on Channel 4 in 2014 (the Beeb turned it down – the shame) with fans patiently awaiting a fourth season that was confirmed before the third had even begun. It’s hard to define exactly the secret to the show’s success but it’s no punt to assume it’s to do with Horgan’s working relationship with co-writer Delaney, whose collaboration began after they “met” on Twitter.

Horgan agrees: “I think there’s a weird alchemy there – something that’s hard to put your finger on. I think sometimes Rob doesn’t know how funny he is until I burst out laughing and write it down. Then when I read it back, he bursts out laughing. It’s pretty bonkers.”

With the series having been off screens for just under a year (the series three finale – the final appearance of Delaney’s on-screen mother, played by Emmy Award-nominee Fisher – was broadcast in April), Horgan is more than willing to tease forthcoming episodes.

“We’re writing it at the moment and we film in July,” she confirms. “I think we always end the previous series with a big question mark that we don’t know the answer to. Then you spend a few days together and start figuring it out. We spend a lot of time working on our outlines to figure out where the series is going. It’s the rewriting that you figure a lot of the more difficult stuff out.”

Horgan and Delaney in ‘Catastrophe’: the next series will be lighter than the previous three, she says

The most recent series ended with a precarious situation for the central couple, with Rob on the cusp of failing a breathalyser test following a car accident, capping a run of episodes that merged equally as much drama with the usual dose of comedy. Horgan’s insistent there’ll be no such darkness this series, describing it as “lighter” than the first three series.

“I guess [the darkness] is intentional in that we decide we’re going to talk about alcoholism or deal with depression and illness in the family. I know we’re not picking the lightest of subjects, but we’re certainly not deciding we have to go dark. In a weird way, this latest series feels pretty light at the moment – and I think that’s because we don’t want to get lost in the drama of it.

“We do want to talk about stuff that people respond to because I generally feel people like seeing issues they have in their own lives reflected on screen, and when it’s done through comedy, it feels even better. But at the same time, we’re really aware it’s a comedy show and we want to make sure it’s really funny so at the moment, it’s feeling lighter than the other series. But we’ll see what happens in the rewrite.”

‘Game Night’ is in cinemas from 2 March