Derry Girls star Nicola Coughlan talks about Big Mood, a dark comedy about female friendship

But now their thirties are looming, and life’s getting more serious. With their careers – Eddie’s as a Dalston pub owner, Maggie’s as a playwright – both reaching rocky territory and Maggie’s bipolar disorder making an unwelcome return, they’re being forced to take a long, hard look at their codependent friendship and whether it really serves them.

Comedy series Big Mood, starring Bridgerton and Derry Girls’ Nicola Coughlan as Maggie and It’s A Sin and Inside Man’s Lydia West as Eddie, portrays a pivotal moment for this pair of besties. The future’s at their doorstep, and with their friendship under threat by big life decisions and the complexities of dealing with a serious mental illness, questions are being raised about whether their friendship can survive in its current state.

There are truly hilarious lines, a brilliant Love Actually-themed 30th birthday party (including a cameo from Joanna Page), the re-appearance of handsome exes at the worst moments, and even a steamy run-in with an old school teacher, but it’s also got a lot of heart.

Darkly funny, emotional and relatable, the series – written by Coughlan’s long-time friend Camilla Whitehill – paints a refreshingly honest picture of female friendship and of severe mental illness across six episodes on Channel 4.

Irish actress Coughlan, 37, spoke about her friendship with the Big Mood writer and why she loves this series.

She says: “I mean, I’ve known this witch for 15 years! We met at drama school, and we just made each other laugh so much. She was training to be an actor – she’s a very good actor, but she refuses to do it, it’s rude.

“It was kind of amazing that through our twenties we still persisted, because all signs are pointing to: I don’t really think that these careers are gonna happen for you girls. And I always wanted us to work together.”

Coughlan adds: “The script was just brilliant, and it’s so her voice. It feels fresh, authentic. From people I’ve shown it to, they were like: I feel like it’s going to teach people a lot about mental illness and stuff. And I’m like, yeah, but ultimately what she wanted to do was write a really funny comedy.

“And also it’s the way we talk to (one) another. It’s not based on us by the way, I feel I have to tell people that!

“It was such a balancing act. Camilla had done it perfectly in the script. It was knowing that she’s this very depressed person, but still having her be funny.”

Big Mood starts on C4 at 10pm on March 28.