theatre

"In the early 1980s, quantum physics hadn't arrived in the way it has now. Insignificance didn't have a single quantum physics joke in it," says Terry Johnson, whose 1982 play about Einstein and Marilyn is revived at the Donmar Warehouse next week. Johnson has now rectified this lamentable situation. "Quantum physics has arrived in the play in an interesting persona. That of an animal," he says mysteriously.

Other than this, the fact of restaging the play, which is set in the 1950s, has thrown up some interesting conundrums. "In the early Eighties the paranoia over the cold war had lots of resonances with the same paranoia in the Fifties. Now that the cold war's over, it gives the play a historical feel," he says. But any rewrites he had done have been to do with craft, not anachronism. "I'm a better writer now than I was," he laughs. "I've calmed down a bit, made it simpler."

Judy Davis took on the daunting role of Marilyn in the original production and now Frances Barber (above) returns to the stage for the first time in three years to slip into those Monroe slingbacks. What prompted the playwright to take the dangerous step of portraying historical figures on stage? "I think it was down to inexperience," he candidly admits. As a director-writer, he is keen for a degree of verisimilitude but doesn't, of course, cast purely on physical similarities. "Actresses who resemble Marilyn often don't convince, but if people are real, audiences trust that." After all, Insignificance is not a biography of Marilyn or Einstein. "It's a history of America seen through those pairs of eyes," Johnson says.

'Insignificance' opens at the Donmar Warehouse, WC2 on 7 Jun (previewing now) (0171 369 1732)