Derry Girls star says Sister Michael "confronts her own issues" in season 3

"She hits a few challenges where she's forced to, just like the girls, grow up herself," she teased. "And she's forced to confront her own issues a little bit. And a bit like being mean, it's very easy to stay complacent.

"It's very easy to stay cynical and sarcastic. It's a very passive thing. And there are a few things in this series that force her to stand up and actually take account of herself and of what she believes. So I think Sister Michael becomes more herself. It’s really lovely."

McSweeney, who has a starring role in upcoming ITV series Holding, also promised that her Derry Girls character still delivers some of the most memorable one-liners this season.

"Yet again, I have some of the best lines in the series. Structurally, it's a f**king gift. Everybody gets to work on setting up the gag, I come in, hit the punchline, and then leave again," she said.

However, she found that returning to set to film the final season proved "bittersweet" due to both the filming restrictions imposed during the pandemic, and to an injury sustained to her leg before filming began.

"[It was] bittersweet," she said. "Everybody who is in this, the show has changed their lives. There isn't a person who's sort of gone, ‘Oh, yeah, my life is the same.’

"The really sad thing about it is COVID made things incredibly difficult for any kind of closeness because we were all in our bubbles. Everybody had to be very careful. Also, because of my leg, I was in an awful lot of pain and was still on crutches.

"It's a pity, but people had it worse. It was lovely to get back into the habit, and then immediately things start coming back. It's like riding a bike, except one you don’t f**king fall off, Siobhán," she joked.

Derry Girls season 3 has long been in the works, with delays due to the pandemic. In an exclusive RadioTimes.com interview that took place on Friday 22nd October 2021, Nicola Coughlan said she would be "in Belfast filming on Monday morning" for the third and final season of Derry Girls.

Of the third season, the Bridgerton star said: "I think it's a lot more of an epic scale this time. Lisa [McGee, the show's creator] knew she had huge ambitions with this one, [with] what she wanted to do.

"She's a genius. Like, there's not really any other word for her. She just – everything is so brilliantly balanced and nuanced and the characters, there's so much detail in every single character in those scripts."

Additional reporting by Abby Robinson.

Siobhan McSweeney stars in Holding, which will begin airing on ITV on Monday 14th March at 9pm. Check out our Drama hub for more news, interviews and features or find something to watch with our TV Guide.

Derry Girls is available to stream on Netflix (season 1) and All4 (season 1 and 2). Looking for something else to watch? You can also check out our guide to the best series on Netflix and best movies on Netflixe.