"I'm not a comedian," says Felicity Montagu pointedly. The Yorkshire-born actor is most famous for playing Alan Partridge's hilariously strait-laced, put-upon PA Lynn Benfield - one of the best-loved characters in a British sitcom - but is keen to stress that she never performs a part for laughs.
"Somehow there's something about me that's funny. Each character I play I always take incredibly seriously. I've had arguments with producers when they've said 'I want you to send it up', and I won't. Why should I do that? I get a lot of satisfaction out of playing characters straight, knowing that it's truth."
Montagu will be demonstrating her serious dramatic pedigree again when she appears in Shakespeare's romantic fantasy A Midsummer Night's Dream, which is being screened as part of the National Theatre Live initiative.
She portrays the amateur playwright Peter Quince - reimagined as Mistress Quince, as it's traditionally a male role - in a cast that includes Game of Thrones' Gwendoline Christie as Titania and Hippolyta, and Oliver Chris as Oberon. The immersive, dark-edged production with a modern soundtrack was directed by Nicholas Hytner at the Bridge Theatre in London.
"We finished five weeks ago," says Montagu. "It was exhausting, we did it to nearly 1,000 people every night."
Hytner's take on the story examined themes of sexuality and gender, swapping the lines of Oberon and Titania, the feuding woodland fairy King and Queen who cross paths with four runaway lovers and Quince's troupe of actors, leading to all sorts of magical events.
The audience, who followed the action at the Bridge Theatre on foot, was confronted with a stifling atmosphere to begin with – Hippolyta is held in a glass booth, with aspects of staging clearly inspired by a certain dystopian novel by Margaret Atwood.
"I think it quite delighted Nick," says Montagu, who’s refined and sharp in conversation – nothing like the meek, purse-lipped Lynn. "He'd watch the audience thinking they were coming along to a real laugh, and then they were put through the first 20 minutes of The Handmaid's Tale with very stentorian choral singing."
Her Quince, she says, was 'very much a mistress'. "She was your benign, misdirected coach of a very bad drama workshop. She hadn't got an ounce of talent or clue what she was doing, but she had good intentions."
Montagu has also been seen on the small – and big – screen as Sue, the bosomy vicar's wife who perennially feasts on cake in Julia Davis' series Nighty Night, and bossy Perpetua in the first Bridget Jones film. She trained at the prestigious Webber Douglas Academy of Dramatic Art, and accepted a lot of theatre work after graduating, but her years in TV and film meant she took a long break from the stage. Consequently, the last time she'd played Shakespeare was in her 20s, as Lady Macduff in Macbeth at Nuffield Southampton.
Montagu ended her hiatus from the theatre in 2013 when she acted opposite Rowan Atkinson in a revival of Simon Gray's Quartermaine's Terms, directed by Richard Eyre.
"I received a letter from Richard saying he'd like me to play this role," she says. "I just thought 'I can't do this, I can't go back in front of an audience, how do you do it?' A lot of actors have that crisis of confidence. Really what you should do is keep your hand in."
The director held a 'doctor's surgery' before press night and Montagu expressed her fears.
"I just said 'I'm terrified, Richard, I want to do a runner'. And he went 'Well, no, you're not, Felicity, not after weeks of rehearsal. You're going to get out there and show them you can do it'. That's exactly what I did. I was very lucky that for my first theatre job after all those years of bringing up kids and earning money for the family, I had Richard Eyre supporting me and giving me such fantastic direction."
Viewers first set eyes on Lynn in 1997, when the series I'm Alan Partridge took Steve Coogan's monstrous broadcaster out of his chat show setting and into the 'travel tavern' where he lives after splitting from his wife Carol. The scripts – by Coogan, Armando Iannucci and Peter Baynham – sparkled and put Lynn in some priceless moments, from being accused by Partridge of 'always going on' about Israeli Prime Minister Benjamin Netanyahu to being informed by the bitter radio host that her life is 'technically not worth insuring'.
Montagu came up with her character's key traits through improvisation with Coogan, Iannucci and Baynham.
"They definitely had a remit," she says. "It was based on a certain person, we legally can't say who it is. I mixed and matched a lot of people I knew as well. I brought her mother into it, they killed her off, and then I brought her boyfriend in – I thought 'To hell with it, they're not going to kill everything off for me'. But they're a very determined team. There was a lot of collaboration."
Lynn popped up again in the Partridge movie Alpha Papa and This Time, the One Show spoof that aired earlier this year.
"Steve is very generous and always wants Lynn around when it's appropriate," Montagu says. "He's doing this series at the moment where he's on his travels, and he says 'I'm sorry you weren't in it'. I would love to be Lynn again, but we'll see. It's great to work with people you know very well and you have a shorthand with, like Julia Davis and Steve."
She doesn't often get recognised as Lynn in the street, she says – instead people are more likely to know her from Bridget Jones or the children's programme Hank Zipzer, in which she plays harsh teacher Miss Adolf. "Men in their 30s or early 40s will say, 'Are you Lynn? You don't look like her but you sound like her.'"
Montagu's last outing with Davis was Sally4Ever, another of the writer-director's outrageously pitch-black comedies about a woman who starts a same-sex relationship with a psychopath she can't get rid of. Montagu played Eleanor, a wheelchair-using work colleague of the title character who may or may not be genuinely disabled. One of her final scenes in the last episode found Eleanor dressed as Puss In Boots, straddling her wheelchair while having pictures taken in an excessively lustful way for an online dating profile.
"I've never seen that scene, actually, because it's on Sky," says Montagu. "My son hasn't seen it or my daughter and I'm sure they'd be traumatised."
She doesn't think Sally4Ever will return. "I would love to do another but it's up to Julia. She's a very nice person. And she doesn't compromise – if she doesn't want to do something again, we understand. We're disappointed, because it would be fantastic to do a second series and to work with her, but we all get it. There's no point nagging her, or calling or texting. She'll do everything in her own time. I think eventually she'll do movies, a one-off project that she loves."
Montagu was born in Leeds – her mother was from Brisbane and her British father was in the military, serving in Burma and India before entering industry. She grew up on Oakwood Grove, near Roundhay Park, went to private school Gateways and took dance classes in Harehills.
"I have a lot of Northern influences in me, in a way, which I can use when I do characters. As a little girl people were very warm and kind, it was a great place to grow up. People were very unaffected and generous. I have seen changes. A lot of people have moved up there now because it's cheaper. Now it's a lot more sophisticated. Roundhay was always quite posh, it had lots of doctors and lawyers living there."
Montagu, 59, has a daughter, Olivia, and a son, Luke, with her former husband, the producer Alan Nixon. She agrees her career now involves 'juggling' television, movies and the stage.
"I'm going to be doing a role in a film called Miss Marx, shooting in Belgium and Rome in November and December, which is lovely. I suppose then I'll have to start looking around for TV or theatre work. Now my children are grown up it's a different ball game."
A Midsummer Night's Dream will be shown on Thursday, October 17. See http://ntlive.nationaltheatre.org.uk for details of venues and screenings.