Siobhán McSweeney: ‘​Without sounding woo woo, I think a feminine spirit has come back to Ireland’

The actor and presenter Siobhán McSweeney, 43, grew up in the village of Aherla, County Cork. After completing a science degree at University College Cork, she moved to London to study at the Central School of Speech and Drama. Her breakthrough role was as Sister Michael in the sitcom Derry Girls. She is currently hosting The Great Pottery Throw Down and next appears in the Disney+ superhero comedy series Extraordinary.

You were on crutches during last year’s Pottery Throw Down after a bike crash which broke your leg in two places. You seem thrilled to be back and crutch-free for the new series…
That’s because I’m on strong painkillers [laughs]. No, I’m genuinely excited. Gladstone Pottery [in Stoke-on-Trent, where the series is filmed] isn’t built for crutches and I was in so much pain. I had to miss a few episodes and felt like I’d let everyone down. So it’s absolute bliss to be back. I’m not that good an actor to fake how much fun we have.

What’s the secret of the show’s appeal?
The potters and their work. I think viewers are sick of high stakes, shouting and silliness. We want to see nice people make nice things. The potters are proper enthusiasts, pursuing their passion, trying out stuff and learning.

Apparently Brad Pitt is a big fan and has seen every episode.
Isn’t that hilarious? Why not? I’m a big fan too.

Judge Keith Brymer Jones has become a cult hero for getting so emotional. What’s that like to witness up close?
It’s so lovely. I adore Keith and his crying is the eighth wonder of the world. But the way people react to it is nuts. Have we fucked up our men so much that to see one weep over a jug is such a rare sight?

I hear you’ve been put in day care this series to keep you out of trouble?
I kept annoying people by wandering into shots and trying to have a go. To distract me, they set up a table where I could try out whatever the potters are doing. There’s a corner backstage which we call pottery day care, with clay and paints. I have to wear a towel over me. It’s like the infants’ table at nursery but I love it.

Later this month, we will see you in the Disney+ comedy series Extraordinary. What’s the premise?
It’s set in a parallel universe that looks like contemporary London. Except in this world, when you hit 18, you develop a superpower. I play Mary, whose eldest daughter Jen is 25 and her power hasn’t kicked in yet. So it’s the story of Jen going through life feeling like a loser because she hasn’t got anything sorted out. She blames it on not having a superpower, but of course everybody feels like that in their 20s. I certainly did. Fuck it, I feel like that in my 40s. The superhero aspect is incidental. It’s a clever framework to explore the universal human story of feeling crap and useless. But it’s really funny; the funniest scripts I’ve read since Derry Girls.

Does it feel like a Disney show?
Not at all. When the call came through saying “Disney wants you to do a show”, me and my agent laughed solidly for about 20 minutes. I assumed it was a kids’ show, then I read it and went, “This is not a fucking kids’ show.” It’s witty, cool and made by Sid Gentle Films, who did Killing Eve.

What would your own 18-year-old self make of Siobhán today?
I think she’d like the hair! She’d be proud because she used to wish and pray every night on the first star she saw that she’d be allowed to be an actor.

Were you happy with the final series of Derry Girls? Was it the right time to end?
Yes and yes. Lisa [McGee, writer] was right to finish it when she did, it was a really classy move. I haven’t been able to watch the hour-long episode since because it broke my heart. She went out on a high by bringing together everything that’s important about that show. They all got the ending they deserved. I can hang up Sister Michael in my wardrobe of old characters, knowing she’s safe now and living her parallel life.

Have you seen fans on social media calling for a Sister Michael spin-off series?
It’s a great compliment, the way people took all those characters to heart. I suppose Sister Michael provokes the imagination. You want to know what she’d make of things. Like: “What would she have to say about this now? Probably something sarcastic.”

Did you steal any souvenirs from the set?
I have her Aran jumper. I didn’t want the wimple because I hated it. That woman looks back at me in the mirror every morning!

Derry Girls and The Great Pottery Throw Down are both Channel 4 shows. Were you relieved when the government abandoned its privatisation plans?
I was delighted, of course, but also irritated by the whole discussion to begin with. I’m insulted by the lack of intelligence of these rotten people meant to govern us. It’s not about disagreeing with policies, it’s Nadine Dorries being stupid. That entire idea of privatising Channel 4 was petty and ignorant.

You’ve also made a documentary about St Brigid. Was that a passion project?
She’s my confirmation name, for a start. St Brigid was big in my household growing up. St Patrick hogs the spotlight but St Patrick’s Day has evolved into something so gross; it’s just for students to get drunk and throw up on steps. It has nothing to do with Ireland. St Brigid is a great lens through which to look at contemporary Ireland. She became a figurehead for Repeal the Eighth [amendment] and without sounding woo woo, I do think a feminine spirit has finally come back to Ireland. We’ve thrown out the dour masculine authority of the church and patriarchal amendments to our constitution. A wave of feminine energy is wiping away all these manmade things to reveal the country I recognise: partly pagan, matriarchal, intelligent and powerful. The documentary traces her history and modern resonance. It airs on Irish TV on 1 February. Hopefully it’ll make its way over to the UK too.

You’re back at the National Theatre this spring, right?
We go into rehearsals next month for Dancing at Lughnasa with an extraordinary cast. I’m reunited with my beloved Louisa Harland, who played Orla in Derry Girls. It’s my fifth show there. Theatre used to be my bread and butter. When I think of acting, it’s always the lights around the mirror and the red velvet curtain. Dancing at Lughnasa has chocolate-box connotations but we can be very snobby about accessibility. I often think that comedy is the way we explore our humanity, more than tragedy. Sometimes people don’t take its profundity, craft and intellect seriously.

How will your leg cope with the dancing?
It might need to be renamed Swaying Gently at Lughnasa [laughs]. We’ll figure something out.

• The Great Pottery Throw Down airs on Sundays at 7.45pm on Channel 4. Extraordinary streams on Disney+ from 25 January