Alison Brie: Mad about the girl

She is best known for her role as Pete Campbell's wife, Trudy, in Mad Men, but her comic timing and convincing British accent reveal she's destined for big-screen success

There aren't many actresses who can move between drama and comedy without seemingly pausing for breath but Alison Brie, who plays both Pete Campbell's likeable wife Trudy on Mad Men and perfectionist Annie Edison on quirky sitcom Community, makes it look easy.

As the ever-optimistic Trudy, happily ensconced in the suburbs with her young daughter, Brie is equal parts playful flirtation and eager expectation – one of this season's funniest scenes involved her refusing to allow Don to pull out of her dinner party, while her committed Charleston with Pete at Roger's disastrous season three party was touching when it could have been laughable.

Meanwhile, as Community's Annie – the second season of which is currently airing on Sony – she is both martinet and schoolgirl, laying down the law to her fellow students while embracing every craze on campus with all the peppy enthusiasm a former school swot and ex-Adderall addict can muster.

Both performances share a warmth at their core but so different is the 29-year-old Brie in each role that many people don't realise it's the same person. "I'm very lucky to be doing both shows because I'm not boxed in," she admits, laughing when I tell her it took my husband two years before he realised that Community's Annie was also Trudy in Mad Men.

"It's a great compliment when people don't recognise it's me... I still get people doing it the whole time they'll go 'Wait, you're on Mad Men?" or 'Oh my God, you're the girl from Community too'. They always seem so shocked."

Indeed, when Brie signed up for upcoming comedy The Five-Year Engagement, which opens here later this month, producer Judd Apatow was surprised to discover that the actress doing the spot-on British accent [Brie plays Emily Blunt's younger sister] also plays Trudy Campbell. "I'm such a fan of Mad Men... and I had no idea who she was, I didn't know that she wasn't from England," he said. "Afterwards, someone said, 'She's on Mad Men and I thought 'what is the matter with me, how much cholesterol medication am I on that I didn't notice that?' She's so great."

While Brie is delighted with Apatow's praise, she downplays the suggestion that she fooled him entirely. "Judd's a massive Mad Men fan so I'm pretty sure he knew I was Trudy," she says sardonically. "Although he did seem convinced I was British. He congratulated me on how great my American accent was in Mad Men. I was all 'no wait, that's the real accent, that's how I sound.'"

If the engaging Brie sounds unusually relaxed about her rising profile, it's because she grew up in Hollywood without being part of it. Her mother works at a non-profit agency providing services for children at risk, her father is a musician and entertainment reporter and there's a sense that being raised in a loving but laid-back family – "my parents are definitely reformed hippies", she admits – imbued Brie with a realistic sense of stardom's pitfalls.

"A lot of people come to Los Angeles and think that they're going to be famous, just like that," she says. "They're coming from the wrong place. I'm very grateful that when I said I wanted to be an actress my parents signed me up for community theatre classes. It meant I learnt to respect the craft, not take it for granted." Nor did she expect fame to arrive overnight. "I did some really random jobs before working on Mad Men and Community," she says. "I did everything from horrible B-movies to regional theatre." Most notoriously, she was also a clown at children's parties. "Yeah, that was crazy," she admits. "I was quite young, 17 or 18, and I can't believe how brave I was, going to entertain 30 seven-year olds for two hours." She pauses. "I learnt a lot about crowd control."

In 2010, a raunchy comic monologue she had performed about her disastrous sex with a gay friend at college who wanted to sleep with a woman was published in online magazine Nerve.com and became a viral internet hit. "I was a bit naive about the power of the internet," she says now. "It was written as comic story, it was embellished for effect and it became this huge thing. My mum finds it hilarious because she'd seen me perform it. My father was more shocked... We had to talk."

These days, the buzzed-about Brie has people talking about her talent rather than her college affairs. Yet her instinct remains to downplay her growing success. "Honestly, with The Five-Year Engagement it was incredible just getting the job," she says. "It's a very different role from either Annie or Trudy and Judd's such a big deal in the comedy world that it could have been intimidating, particularly with the amount of improvising we had to do. But they were all very welcoming, although I always felt I was a little on the back foot because I had to think about the accent first. I don't know what you guys will think. Emily was nice about it – I just hope she was telling the truth."

Not that she has much time to spend worrying about accents. The fifth season of Mad Men, currently airing on Sky Atlantic, has seen Trudy blissfully playing homemaker in the suburbs even as Pete, feeling trapped, attempts an affair with a fellow commuter's wife and struggles with depression. The increasingly dark storyline – episode eight was filled with the imagery of death and there has been much speculation about Pete's possible suicide – resembles a John Cheever short story, detailing the price you pay for settling for someone else's dream and ensuring you feel for Pete, flaws and all.

Making it all the more depressing is the audience's recognition that Pete is blind to his greatest asset: his wife. Trudy has always supported her husband. If he had ever respected her enough to tell her the truth about anything, she could have been a source of great strength.

"I know, that's why it's so awful," says Brie. "Trudy's really happy, she thinks that the marriage is great, that they're doing really well. She's a very optimistic and straightforward person who, yes, is a little bit spoiled but who's actually grown throughout the series. And then you have this very dark parallel storyline playing out with Pete... There are times when I just want to shout: 'How can you be so unhappy? You're with Trudy.'"

Not that it's all suburban angst. Away from Mad Men, Brie has started a musical side project with two of her closest friends – "It's a hobby really" – and recently learnt that the acclaimed but perennially low-rated Community has been granted a fourth season. As to the future, she remains pragmatic. "I'd love to do more movies and keep trying different genres but I know how lucky I am to be in Mad Men and how lucky I was not to have to choose between that and Community. It's amazing that I got to do both."

The growing army of fans, both male and female, who love Brie's down-to-earth charm and earthy humour, would undoubtedly agree.

'Mad Men' is on Tuesdays at 9pm on Sky Atlantic; 'Community' is on Tuesdays at 10.30pm on Sony TV; 'The Five-Year Engagement' opens on 22 June

Selling themselves: How the other Mad Men stars are raising their profile

Jon Hamm

Hamm, aka the dashing Don Draper, is cornering the market in handsome cads thanks to sharp performances in 'Bridesmaids' and 'Friends with Kids'. He also starred in crime drama 'The Town', appears as Dr Drew Baird in sitcom '30 Rock' and recently went behind the camera to direct episode three of this season's 'Mad Men'.

Christina Hendricks

Eye-catching turns in 'Drive' and Tony Kaye's 'Detachment' have seen Hendricks, who plays curvaceous office manager Joan, move smoothly into film. Next up is Mike Figgis and Neil LaBute's 'Seconds of Pleasure'.

John Slattery

In addition to playing on his smooth-talking silver fox reputation in car commercials, Slattery (who stars as Roger Sterling) has also directed a number of episodes of the show and occasionally turns up looking slick in thrillers such as 'The Adjustment Bureau'.

Elisabeth Moss

While Moss, aka ambitious Peggy Olson, has had no shortage of film offers, her best away-from-'Mad Men' reviews have come in the theatre, with critically acclaimed performances in 'Speed-the-Plow' on Broadway and 'The Children's Hour' with Keira Knightley.

Vincent Kartheiser

Despite a commanding performance as the weaselly yet vulnerable Pete Campbell, Kartheiser has yet to land a big movie role. He provided a rodent's voice in animated Western 'Rango' and popped up as Amanda Seyfried's father in Andrew Niccol's so-so sci-fi film, 'In Time'.