'Intriguing isn't it?': Tamsin Greig mulls over life's mysteries

Why does everyone want to know what it’s like to kiss Matt LeBlanc but not Stephen Mangan? Why do people only want to know about her marriage if it’s wracked by jealousy? Why is laughing likely to tip over into crying?

Interviewing an actor is usually a straightforward transaction. Steered by questions from the journalist, he or she embarks on a monologue of variable length and interest. Interviewing Tamsin Greig, however, is a different proposition, as it requires dialogue. Lots of it. Direct and engaging, with a fondness for the word "intriguing" and the sort of unhesitating eye contact that is surprisingly uncommon in her profession, Greig wants to have a conversation. There's much to talk about, not least the fact that she finds herself back in the theatre, somewhere she has flourished of late. But whether she's on stage or television, she inhabits a place she has made her own, the fruitful intersection between comedy and drama.

Although she was a stage actress initially, it was through two idiosyncratic television series that Greig rose to prominence: Dylan Moran's anarchic bookshop-set comedy Black Books, and the much-loved, surreally tinged hospital drama Green Wing. We've seen a lot of Greig on our screens recently, in the likes of Friday Night Dinner and White Heat, but above all she has starred in Episodes, the second series of which finished last month. This glossy British-American co-production follows the travails of Beverly (Greig) and Sean (Stephen Mangan), husband-and-wife comedy writers who attempt to transfer their hit sitcom to the States and acquire former Friend Matt "Joey" LeBlanc as their star along the way.

The easy chemistry between Greig and Mangan, another Green Wing alumnus, is a sizeable part of the show's appeal. However, Episodes also offers a masterclass in Greig's particular skills, illustrating how she is prepared to pause a little longer than most actors, the camera lingering on her expressive, soulful eyes. But Greig's talents alone won't win it a third series; I ask her if its fate depends on very Episodes-like concerns over American ratings and whether it's up against a show with talking dogs. "Those things," she says softly – and never has someone given two such innocuous words such heft – "are things that matter but I don't understand [them]," and here she lowers her voice to a conspiratorial whisper, "or really care about [them]."

Should a third series be commissioned, would she like to carry on pottering around Mill Hill and Chertsey, pretending she's in California? (Most of the show is filmed over here.) "I don't ever want to do stuff just for the sake of it," she says. In the meantime, all anybody seems to want to ask Greig is what it was like to kiss LeBlanc (their characters have a fling). "Everybody asks me that. Why has nobody said to me, 'You kiss Stephen Mangan all the time, what must that be like?' What is it about Matt LeBlanc? It says so much about that show [Friends] and the place it occupies in people's lives. Intriguing, isn't it?"

I have a different Matt LeBlanc question: would his degree of stardom appeal? Greig pauses, searching for the right words. "There is a level of visibility that is attached to him that he handles with incredible grace, but I don't know that I could ever live like that. With that level of being known you become a kind of possession, and I do love being anonymous. I love fitting in." But surely you're recognised a lot? "Yes, well… Most people just want to say, 'Thank you,' but every now and then you get hilariously inappropriate comments. Like people saying, 'It's amazing, because you look so different in real life. You're much younger on the telly!' Yeah, thanks for sharing that."

The writers of Episodes, not least Friends creator David Crane, have enormous clout in Hollywood, so I wonder whether Greig was tempted to try her luck when she was over there. "My agent [and I] did spend a couple of days going round having meetings. The networks are amazing; they meet people all the time. I don't know how much came of them, but you know, I never say never." So you'd be prepared to upheave your husband and three children from home in London? "When I was offered the season at the RSC [in 2006, when Greig played Beatrice in Much Ado About Nothing], I said, 'No, come on, that's impossible.' My youngest daughter was 18 months old and it would have meant going to live in Stratford. It was my husband and my agent who said, 'OK, but is it impossible?'"

Luckily for everyone, it wasn't. Greig triumphed in the production, highlighting her similarities to Emma Thompson, another actress who started out with comedy and discovered that her skill-set was much broader. Her performance in that bittersweet comedy earnt her both Olivier and Critics' Circle awards, relaunching a rewarding stage career that has since seen fine turns in David Hare's New Labour drama Gethsemane at the National Theatre and as a fraught parent in Yasmina Reza's The God of Carnage in the West End. Which brings us round to Jumpy, April de Angelis's Royal Court hit that is about to take its rightful place in the West End, with Greig once again leading the cast as Hilary, an anxious 50-year-old whose teenage daughter is threatening to go spectacularly off the rails. It's a terrific piece, about sexuality blossoming and fading, about married couples rubbing along and wondering whether life will offer any more surprises.

Above all, it finds Greig once again profiting from that faultline between comedy and drama. "Laughing and crying are very similar," she says. "They're an extreme response to life. You see it in children who start laughing hysterically. Very easily it will tip over into hysterical tears, which is why mums don't want children all wound up at bedtime. It's the same muscular movement, so I'm intrigued about that."

I mention one exchange in the play that particularly resonates, when Hilary and her husband Mark are lying in bed, trying not to listen to their 15-year-old daughter Tilly having sex in the next-door bedroom:

Mark: "We're not doing things right."

Hilary: "This is what happens now."

"Those two lines seem to me to sum up the entire play," Greig says and, it transpires, much of her world view. This theme of modern life being at odds with what is desirable or even "right" is one to which Greig returns frequently. So do the parent-child conflicts in Jumpy resonate with her, either as mother to children aged seven, 12 and 13 or as a former teenager herself? "This play is like a preparation for what may be around the corner!" She laughs. "My father was 60 when I was born, so you did not speak like that [Tilly is very fond of swearing]. I was a middle child and, I'm sure, prone to inexplicable shows of emotion, but my overwhelming memory is that if you chose to use those words, the consequences were not things you would want to live with."

Greig thinks she inherited her desire to act from her mother, a keen player in amateur dramatics when she lived abroad with Greig's father, a colour chemist who created dyes. ("Someone once said, 'Wow, he was a rainbow man,' but he was as far from being a rainbow man as you could possibly get.") Practicality ruled at home in Kilburn, north-west London, with her father recommending a drama degree at Birmingham University rather than drama school. Her mother suggested a secretarial course afterwards, to ensure that Greig had all her bases covered. It was winning, in 1991, her ongoing occasional role in The Archers as Debbie Aldridge that finally convinced her father of her career choice. "I think he sat up and thought, 'Ahh, there might be something in this.'" She met her husband, actor-turned-writer Richard Leaf, at a wrap party for a TV show they were both in. I ask her if there has ever been any jealousy about respective levels of career success. "What is it in us that goes, 'Oh yeah, they're jealous of each other'? Why do we want to hear that story?" For the record, she says, there hasn't been. "You either agree to do it together or you don't," she says firmly.

As coincidence would have it, Stephen Mangan is appearing on the Royal Court's main stage at the same time as Greig is rehearsing upstairs in the building. "She's got great comedic chops, as she knows her way around a joke," says Mangan. "There's a great warmth about her as a person and she brings that to everything she does." Let's put the record straight, I say – what is it like to kiss Tamsin Greig? "She's a better snog than Matt LeBlanc, put it that way."

One place where we could usefully see Greig and Mangan kissing would be on film, but for that British cinema would have to get over its almost pathological hatred of the middle class. If Greig spoke French à la Kristin Scott Thomas, we'd see her in a new arthouse gem every other month, I suggest. "To even be thought of [in the same way] is an encouragement," she says. "But what sort of films do we make in Britain? Stephen Frears [who directed Greig in a supporting turn in Tamara Drewe] says we make The King's Speech or we make This is England, so we experience the extremes of UK living, but the middle ground…" Even so, Greig says she's "proud of the fact there are casting directors who have the courage to ask you to do something that people don't expect of you, in an industry that doesn't want people to be very different. So I'm sitting in a very privileged position, because in Episodes I get to look and play younger."

How old are you, by the way? "Forty six. But what does it matter? Every interview it's 'Tamsin Greig, 46'. They didn't ever write, 'Winston Churchill' and then his age." But what about the received wisdom that things get tough for actresses over 40? "People say, 'Oh yes, you're going into the fallow years when it all dries up for women, work-wise and body-wise. Well, at the moment it's all very verdant! Maybe now is a good time to fill up the storehouses and prepare for the possibility of lean times."

Lean times look very far away, with a second series of Channel 4 comedy Friday Night Dinner due to be broadcast in the autumn, and the possibility of more episodes of Episodes. She'd love to have a crack at Chekhov, Ibsen, Strindberg and more Shakespeare and for my money, a canny producer could do far worse than turn Jumpy into a film. And, of course, there's always The Archers. Does she feel some of the storylines have been a touch sensationalist recently? "I think a lot of it is also very mundane! So it's a great balance, isn't it?"

With our time together drawing to a close, Greig surveys my notes. "You've done some very fast writing there. Well done." You could have done it all in shorthand, couldn't you, I ask. "I can do shorthand, yes. Do you want me to write something for you? What do you want me to write?" I offer her some paper, explaining that I don't have shorthand, so she could put "This has been the most tedious hour of my life" for all I'd know. She starts to write fluently, in highly convincing squiggles. "NOT," she adds sweetly in Roman script at the end, underlining it twice for emphasis. And with that, the intriguing Tamsin Greig leaves.

'Jumpy' runs from Thursday to 3 November at the Duke of York's Theatre, London WC2 (0844 871 7623, jumpytheplay.com)