CAROLINE Mortimer is the nation's favourite TV cook and she has it all. A sparkling career. A big house in Highgate. A (golf) loving husband, smart children and the best kitchen money can buy.

Beneath the immaculate furnishings and studio lighting and away from the glare of the ever-present cameras, however, Caroline must face the looming collision of living a private life in the public eye in Torben Betts's new comedy, Monogamy.

What happens when the cameras turn off and the truth comes out, asks playwright Betts, who, like leading actress Janie Dee, made early strides in his career under Alan Ayckbourn's wing at the Stephen Joseph Theatre in Scarborough.

Fresh from Stephen Sondheim's Follies at the National Theatre, Olivier and Evening Standard Award winner Dee is starring in The Original Theatre Company's world premiere, on tour at York Theatre Royal from Tuesday to Saturday before a five-week run five-week run at the Park Theatre in London.

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Janie Dee in rehearsal for her role as celebrity cook Caroline Martin in Monogamy

"We opened a fortnight ago in Malvern, and it's always terrifying but particularly this one because it's a huge, mammoth role and I'd had to break off to film something in the middle of rehearsals," says Janie, who made the film Official Secrets with Ralph Fiennes and Keira Knightley, cast in the role of (Iraq War) legal advisor Jan Clements.

"Alastair Whatley, who directs this play, very kindly said I could do the film, so we started the rehearsals a week early and I missed only a week and took my lines with me to learn in the evening.

"Making the film was a fulfilling experience but it was also important to get back to rehearsals and thankfully the first night in Malvern was almost word perfect, since when we've been working on it daily, fine-tuning it, as with a new play – and even an old play – you don't necessarily understand it all straightaway. I believe audiences do catch up but they love it if you're ahead of them; that's fine. It's about letting the the play take off and letting them fly behind to catch up."

Playing a celebrity TV chef with a storyline of living a private life in the public eye will bring to mind Nigella Lawson, but Monogamy has a broader reach. "I looked at Nigella, I looked at Delia, who's my favourite, and I talked to a couple of professional chefs I know, but the framework of the play is the most important thing, rather than the celebrity chef angle, and so Caroline goes on a journey in a fresh way and it's much more exciting doing a story where no-one knows where it will turn next," says Janie.

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"The play's got wit, bravery and profundity to it," says Janie Dee of Torben Betts's Monogamy. Picture: Simon Annand

"With Follies, there were different pressures. People would come up in the street and say, 'oh my god, I'm so looking forward to it, it's going to be amazing', but you never know. Sometimes things don't gel, but Dominic Cooke handled it so well; he's a fantastic director.

"The team were amazing to the 'nth' degree, working to take it to another level. When it opened, Stephen Sondheim was there and he shouted out from the corner, 'Bravo!', so that was a night I'll never forget."

Janie had performed in Torben Betts's adaptation of The Seagull at Regent's Park Open-Air Theatre, where he came up to her one night and "rather drunkenly said he'd written a play for me", she recalls. "The play was Monogamy and he couldn't have written anything more resonant for me or for the state of the nation.

"It's a cry out, but it's very, very funny and I love how he makes Caroline feel less alone than she felt. The play's got wit, bravery and profundity to it, which is not a million miles away from Follies in trying to shake things up and make us feel empowered."

York Press:

Writer Torben Betts with Monogamy cast member Patrick Ryecart

As for the title, Monogamy, "it's an interesting one", says Janie. "I started with that aim in my life. It's something you aspire to. It's a romantic ideal, an ideal that so many of us have had, and Torben is exploring different views of it in the play, exploring the sexual and political differences in that word and how we feel about our desire for something that is so difficult to achieve."

Betts's plays are marked by comedy turning ever darker and bleaker. "If you look at Chekhov, Shakespeare, there's humour in all good writing, just as we recognise there are tragedies in life. Torben's is a voice we're lucky to have, like Pinter, Frayn and Sondheim, and a great writer can encompass both comedy and darkness in a play, taking us on a journey that scratches at so many emotions beneath the surface," says Janie.

"He's got the ideal combination, pushing his characters to their limit in every way because he writes about us in all our glories and awfulness with a perspective that's so honest and brave."

Among celebrity TV chefs, Janie first enjoyed The Galloping Gourmet (Graham Kerr) in her childhood. "He was hysterical," she says. "Now I love Delia Smith's sweet, simple English approach to everything. I've got all of her books, and because of this play, I've become really interested in cooking, and on the recommendation of Jay Rayner [the Observer's food critic], I'm going to do some cookery classes with Ukranian chef Olia Hercules. He said 'you've got to meet her', so that's happening."

The Original Theatre Company in Monogamy, York Theatre Royal, May 22 to 26, 7.30pm and 2pm, Thursday, and Saturday, 2.30pm. Box office: 01904 623568 or at