In the past, Rachael Stirling admits, she was "not terribly gracious" when the subject of her mother, Dame Diana Rigg, came up. Now the 27-year-old actress, who ignited the nation's TV screens when she appeared nude, painted gold and wearing a strap-on dildo as the lesbian heroine of Sarah Walters's Tipping the Velvet, can hardly duck the family connection. Not just because she has inherited her mum's looks, colouring and imperious dark-brown voice, but because she is about to play on stage a role originated by Rigg on screen.
With typical inventiveness, Phelim McDermott and Lee Simpson of Improbable Theatre have adapted the 1973 horror flick Theatre of Blood, in which a thwarted, grandstanding Shakespearean actor sets about murdering theatre critics in scenarios derived from the Bard's works.
Jim Broadbent is taking the lead role of Edward Lionheart (played on screen by Vincent Price), and Stirling, like her mother before her, is his loyal daughter, Edwina, who spends much of the play in male disguise.
"When Phelim and Lee approached me about this, I thought it was a setup," she admits. "All my life I've been asked to dress up in a black-leather catsuit, like mum in The Avengers. In the early years, I fought a battle I didn't really need to fight in my own head, about being identified just as my ma's daughter, and now I can be happy and proud about it.
But I'd never seen Theatre of Blood although I knew she was in it."
Watching the camp, overblown film she was "dumbstruck" that it had never been turned into a play before, "because it is really about the passing of the kind of big, heroic acting that died out around the time I was born, and that works so much better on stage than it does on screen".
The new play is being staged at the National Theatre, which McDermott and Simpson have written into their adaptation. They explicitly link it to the 1972 opening of the National, depicting Laurence Olivier's handing of the reins to Peter Hall as symbolic of the passing of the old actor managers' companies in favour of buildings run by professional directors.
"How do you control actors?" says Stirling. "You employ them." And it wasn't the Rigg connection, but Stirling's- other most famous appurtenance-that dildo, that made McDermott-and Simpson think of employing her. "They'd seen me impersonating a boy in Tipping the Velvet," she grins.
"The costume department are making me a cock. It's the second one I've had made for me, although I also played a boy in a film called The Triumph of Love. But then I just had a handkerchief in my trousers ...
"We had a real-life prosthetic, the kind transvestites wear, brought in from New York for this show, but it wasn't big enough. So, they're making me a nine-incher from lentils. I have still got the one from Tipping the Velvet, although it's gone a bit green. I wonder if I'll end up with an armoury of them in years to come..."
Ahem, let's change the subject.
Isn't the idea of killing critics every actor's dream? "I thought it might be rather empowering," she admits, "but actually we end up making a pretty good argument for critics. We went through this bizarre cathartic process in rehearsals where we all read out our own worst reviews and, of course, they were hilarious.
"You come to a realisation that when you get a bad review, the reason it stings is that you have an inner critic that agrees, however slightly.
Sometimes a reviewer can actually give you some good notes." She pointedly declines to name the "one critic all actors wouldn't mind seeing dispatched", but says that her favourite murder in the play is when Merideth Merridew is force-fed his pet poodles, baked in a pie, in a homage to Titus Andronicus.
She chose not to discuss her role in Theatre of Blood with her mother, nor did she consult her over the nude scenes in Tipping the Velvet, even though Rigg had been the first classical actress to appear naked on the British stage, in Abelard and Heloise, in 1971. "When she was described as being built like a brick mausoleum with insufficient flying buttresses," laughs Stirling.
"We don't discuss work all the time, but the great thing now is that I've done enough myself for us to enjoy having this profession in common."
Mother and daughter did, recently, however, perform a long- promised ritual, opening up the treasure trove of old reviews, photos and programmes that Rigg's own mother had stored in a trunk. "We got rather pissed going through this Pandora's box and spent most of the afternoon in tears."
Stirling has always said that acting chose her rather than the other way around. She got her first taste of it at boarding school, after Rigg and her father, landowner Archie Stirling, divorced following his affair with Joely Richardson. (Rachael still spends as much time as she can on his estate, and adores the new stepbrother he had last year with his third wife.) Stirling didn't go to drama school, but got an agent when she appeared with the National Youth Theatre in her teens. She made her first two films, Still Crazy and Complicity, while at Edinburgh University, studying art history and Russian. "Green doesn't begin to describe what I was then," she says. "I didn't know what a camera looked like, what an agent was for. I'd been on a film set with ma once, maybe twice, but I didn't know what the f*** I was doing."
Tipping the Velvet did teach her more about film technique, but it also ushered in eight months of unemployment when all she got in the post were scripts "where my character got her tits out, for no reason, on page two".
A tabloid sensation here, the series gained art-house kudos when screened in the US. After a stint in A Woman of No Importance at the Haymarket in 2003, Stirling capitalised on it by going to Los Angeles.
"I've got an agent there who got me meetings with powerful directors but after a couple of months I thought, what am I doing here? There are things I need to do in London."
She came back, she says, to gain a proper grounding in theatre, first at Hampstead in Anna in the Tropics and now at the National. She lives alone since breaking up with DJ John Lycett-Green two years ago; a rumoured romance with her co-star at the Haymarket, Julien Ovenden, was, she says, made up by the newspapers.
"I'm feeling my way around life, work and love," she says. "I really don't have any set idea of where I'm supposed to be in my career or who I'm supposed to be with, at this stage of my life." Under pressure, she admits that she fancies a crack at bigger films and some Shakespearean roles.
Including, naturally, the crossdressing ones. "I think I'd be a rocking Rosalind," laughs Stirling. "It's about time someone cast me as her."