Simon Russell Beale and Fiona Shaw interview for London Assurance

By Dominic Cavendish Published: 1:12PM GMT 08 March 2010

Simon Russell Beale and Fiona Shaw, who are starring together in London Assurance at the National Theatre Photo: ANDREW CROWLEY

Simon Russell Beale and Fiona Shaw are pity a lounge backstage at the National Theatre, chowing down their lunch snacks and carrying a great old chortle. The approach theyre carrying on he leaping to his feet to burlesque her memorable opening in Electra (1988), she regaling him with a story of a postcard dating from 1993 that had usually usually been sent to her by her individualist mom and youd think theyd been behaving together, on and off, for ages.

Yet the entrance together of these dual heading lights of the British theatre for the useful purposes of Sir Harcourt Courtly and Lady Gay Spanker in a Nick Hytner-directed reconstruction of London Assurance, Dion Boucicaults sparky humerous entertainment of 1841, outlines a initial of sorts. "Ive never looked in to your eyes and pronounced something before, have I?" Beale asks, in his quiet, meaningful nasal way, to Shaws powerful affirmation.

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The pairs most garlanded paths crossed during Deborah Warners brutally complicated prolongation of Julius Caesar, seen at the Barbican in 2005, the throng scenes of that were bulked up with dozens of proffer extras. He was Cassius, she was Portia, and they enjoyed a impulse of unaccepted swindling during one of the some-more uncontrolled episodes of county unrest. "There were about a billion people on stage," Beale recalls. "Ralph Fiennes [playing Mark Antony] was using around, and we had zero to do at the behind but discuss about legal holiday homes."

Before that, they got on identical to a residence on glow during the lulls in the filming of a dinner-party stage in Persuasion, Roger Michells 1995 Austen adaptation, their minds whirring on identical planes of egghead inquiry. Its usually now, though, that fans of both are removing to see what kind of thespian chemistry competence upsurge in between them.

In the play, created when the Irish writer was usually 21, Sir Harcourt, a decayed and loveably stupid fop, falls head-over-heels for Lady Gay, whos energetic, horsey, fox-hunting insane and usually frequency firm by the reins of marital constraint.

With Beale behind at the National after looming in The Winters Tale and The Cherry Orchard for Sam Mendes, and Shaw on the miscarry from the rigours of Mother Courage, additionally at the National, both were drawn to the good-humoured delights of London Assurance. "Were essentially being authorised to do something we havent been means to do for about twenty years, that is high-definition comedy" says Beale, 49, who got his big mangle at the RSC in the late Eighties personification a contingent of Restoration fops.

"What I find so delectable about London Assurance is that the some-more sexual than the Restoration comedies," he says. "Theres a cooperative peculiarity to the writing, and a unconcern to it. Its somewhat off-centre."

For Shaw, 51, the total thing froth not usually with the singular oxygen of humerous entertainment but additionally the sold laughter of nation life, one she recognises from her own girl in Cork. "To me," she says, "the glorious of nation jubilee is something that cant be outdone by all the awards ceremonies in the world. Boucicault gives you that soft mood. The people in this fool around are blissfully free, vital in the moment.

"Of course, nation folk currently have got sport bans or breeze farms to be concerned about, but that universe does endure and I think an assembly examination this has a clarity mental recall of that freedom."

Dont these larger-than-life comic purposes dark in some-more aged with the vital comfortless tools theyve attempted over the years Hamlet and Medea, say? "No, they dont!" says Beale. "You do Hamlet and the an extraordinary impulse in your life. But afterwards you fool around Benedick in Much Ado and thats a utterly opposite clarity of compensation again. Whatever the differences of the role, the routine is the same."

"Of course, this isnt on the same scale as Electra," says Shaw, "but these purposes need in all as most bid to do. Its usually a opposite sort of effort.

"My entrance here was as Julia in The Rivals [in 1983]. Its peculiar not to be personification the immature chairman any more. I cant hold Im the same age as Geraldine McEwan was when she played Mrs Malaprop. That doesnt appear a era ago, nonetheless here I am! How did that happen?"

"Thats really true," says Beale. "Ive got grown men job me "Dad. Thats a big impulse in an actors life." And on that somewhat saddening note, they lurch off together down the mezzanine frequency overwhelmed by more advanced years, it would appear to go and rehearse their nation dancing.

"London Assurance is in preview at the Nationals Olivier Theatre, London SE1 (020 7452 3000), and opens on Wednesday.