Close-up: Olivia Colman

Best known for playing Sophie in the TV sitcom Peep Show, Olivia Colman has a habit of appearing, like a canary, wherever there is British comedy oxygen, with cameos in The Office, People Like Us, Black Books, Green Wing, Hot Fuzz and, of course, That Mitchell and Webb Look, where she played every female sidekick from game-show contestant to Stone Age detective.

With her recent role as the rather fabulous mother Debbie Doonan in Beautiful People, her spot in the modern TV pantheon is assured. Not that she's noticed: "Comedy or straight, it's just a dream to get work at all," she says. "I still can't believe I don't have to go back to temping." Not likely; her next part is in Consuming Passion, BBC4's dramatised history of Mills & Boon, in which she plays a repressed secretary, Janet. "Poor sweet Janet..." she says. "Hasn't really ever had a boyfriend, but has a very vivid imagination. A bit like me as a teenager." Did she ever read Mills & Boon? "No, but" – Colman takes a passionate breath – "I loved Judy Blume."

Over the course of the docudrama, Janet blossoms into a top Mills & Boon author with the pen-name Racquel Pretty. "There is a serious point in that it was an important way for women to start earning their own money," says Colman.

Other pet projects include "a bit of fun" called Le Donk, filmed by Shane Meadows and starring Paddy Considine as a roadie called Le Donk. Colman plays his ex-girlfriend, and her baby boy has a part, too, as son of Donk. "He was five months old, but we pretended he was newborn," says Colman. "It was that kind of silly." Another Donk stunt included stagecrashing an Arctic Monkeys gig. "The band was in on the joke," she explains, "but who knows what the audience thought." No wonder, when work is that much fun, Colman says she would do it "for free. But don't tell my agent." nn

'Consuming Passion' is on BBC4 tonight, 9pm