WHEN Liz Lochhead and Siobhan Redmond talk about being part of a theatrical family, it doesn't just relate to Thon Man Moliere, Lochhead's new play which Redmond appears in at the Royal Lyceum Theatre in Edinburgh when it opens next week. The theatre family that Scotland's former Makar and one of the country's foremost and most fiercely intelligent of acting talents are talking about is something more personal.

Ostensibly a comic study of the seventeenth century French playwright formerly known as Jean-Baptiste Poquelin, Thon Man Moliere finds Lochhead returning to the writer who has arguably been her greatest dramatic influence over the last thirty years. The relationship began when she adapted Moliere's most scathing of satires, Tartuffe, into a ribald rhyming Scots that caused a sensation in 1986 when it first opened on the same stage that Thon Man Moliere will.

Since then, two more adaptations have followed. Miseryguts, taken from The Misanthrope, appeared in 2002. Educating Agnes, adapted from The School For Wives, followed in 2008. With Lyceum associate director Tony Cownie having directed all three adaptations at various points, it seems only fitting that he is in charge of Thon Man Moliere.

“Moliere goes right back through my life, and right back through my friendship with Tony Cownie,” says Lochhead, sitting opposite Redmond in the Lyceum bar on a lunch break from rehearsals. “We became friends on Moliere when Tony played Orgon in a wee profit-share production I did in 1993 to cheer myself up after my dad had died and I had the money to mount it. We worked together on all sorts of things after that, but it keeps popping up. Both Tony and I realised at a certain point that we're both obsessed with Tartuffe. We must be, because we look at how often we've done it and looked at in different ways.”

In Lochhead's new play, Redmond plays Madeleine Bejart, who met Moliere when he was aged nineteen, and co-ran the theatre company Thon Man Moliere is centred around.

“They needed each other, to do what they wanted to do,” says Lochhead, “and they were both stuck with this need to do this crazy thing, which did not always make them happy, but they were artists. It's not a history play. It's an invented kind of version of this dysfunctional family that's a theatre company, but all families are dysfunctional one way or another. .

But, as Redmond observes, “Theatre families generally have better costumes and more jokes.”

Redmond has been a part of Lochhead's theatrical family ever since Lochhead saw her perform in a St Andrew's University revue in 1981, and got her to join her onstage in the Tron Theatre bar in a revue called True Confessions.

“I did this by stalking her,” says Lochhead, “phoning up all of the not very many Redmonds in the Glasgow phone directory. True Confessions was a great wee feminist show. Looking back, it was quite funny and touching in bits, and people like the wonderful David MacLennan and David Anderson loved it. The following year at the Edinburgh Festival Fringe they'd hired a big lump of the Pleasance, and they asked us did we want to sublet a space.”

For what became Tickly Mince, Redmond and fellow actors Kevin McMonagle and John Cobb to perform a compendium of work written by Lochhead with Alasdair Gray and poet Tom Leonard, with James Kelman coming aboard later for a show in which the set was made up of furniture from the writers own homes. Redmond was particularly impressed by Alasdair Gray making his way from Kersland Street to the Tron carrying a settee on his head.

“What was really nice about that period,” says Redmond, “and we probably thought that we were terribly experienced because we'd done True Confessions, was hearing Tom Leonard and Alasdair Gray using all these theatrical terms, and Kevin directing us because we didn't realise that you needed someone to see what you looked like onstage, and not having a clue.”

Lochhead agrees.

“It was this mad family. Tom and Alasdair's satire was just exquisite, and it was all just a laugh. That's why we're still friends. You don't realise when you meet people that they're going to be such close friends for the rest of your life.”

The roots of Thon Man Moliere stem from Lochhead reading The Life of Monsieur de Moliere, Russian writer Mikhail Bulgakov's biography of the French playwright, written between 1932 and 1933 but not published until 1963. Lochhead was gifted the book by another friend, short story writer Helen Simpson.

“Despite being English and Oxford educated , Helen loves my rudest and most vigorously Scots stuff best, and when she gave me this book a decade ago said you are going to write a play about Moliere one day. So I read it, and it's like a novel. It's a brilliant read, but I didn't see a play till about two years ago, when I suddenly thought to myself out of the blue how like Woody Allen, another great comic writer, Moliere was in a certain aspect.

“Once I thought that, it made me laugh, and I thought, looking back on Woody Allen's big scandal, what a pity there weren't photographs in Moliere's day. The thing that made me start writing the play was thinking how I could get round the fact that photography didn't exist then.

“So I started writing the play nearly two years ago, and I'll suddenly feel very empty on the 25th of May, because I think I'll be very lonely without Moliere to argue with. He's good company. You'd want to skelp him, but he's good company. I feel like that about Jimmy Chisholm as well,” she says with a smile about the actor who plays Moliere.

With Lochhead's love affair with Moliere having moved through three artistic directorships of the Lyceum, Thon Man Moliere will be the final show of Mark Thomson's tenure before he passes the baton to David Greig, who announced details of his inaugural season last week.

“I don't think anybody else but Mark Thomson would've said yes to this,” Lochhead says.

Part of Greig's announcement was his intention to have the Lyceum host Sunday night variety nights. “Oh great,” says Lochhead. “I hope they ask us to do it.”

There are certainly similarities between variety theatre and Moliere's own upfront brand of comedy.

As Redmond points out, “There's an extremity about it, which is understood to be both heightened and at the same time completely heartfelt. A lot of that is about addressing the audience directly, or not pretending that the audience isn't there.”

Lochhead describes Moliere as “a major,major comedian, but at the heart of any good Moliere play, there are mysteries. By mysteries, I mean, well, would human beings actually do that? And my heart says, well, yes, they would.

“People writing about him say, oh, he's not psychological, and that if you translate them then just a skeletal plot remains, but I don't agree. I think you get human beings with all their ridiculous complications coming out of his greatest plays. I keep hoping there'll be an undiscovered one and it would have to be a rhymer, because I like doing the rhymers, that would turn up that's got the kind of life in it that I like.”

Like his characters, Moliere was something of an obsessive.

“I think it's good writing plays about obsessions,” Lochhead says, “because protagonists have got to care or the audience won't care. Being quite an obsessive person myself once I get going, for a year and a half I've had no peace. But on May 25 I can get my life back.”

Thon Man Moliere, Royal Lyceum Theatre, Edinburgh, May 20-June 11.

www.lyceum.org.uk