Is Brie Larson the next big thing?

Twenty years later, Larson could be about to become the hottest actress in Hollywood following what critics are calling “a career-making performance” in Room (in cinemas from Friday 15 January). She has already received a Golden Globe nomination, and an Oscar nod looks likely to follow.

Room is based on the bestselling novel by Emma Donoghue that was shortlisted for the Man Booker Prize back in 2010. The story was inspired by the case of Austrian man Josef Fritzl who imprisoned one of his daughters in a basement dungeon for 24 years, where she bore him seven children.

In the film, Larson plays Ma who was kidnapped by a man she calls “Old Nick” (Sean Bridgers) seven years earlier. She is being held in an 11ft by 11ft garden shed with her son, Jack (played by Jacob Tremblay), now five years old, who was born during her captivity.He knows nothing of the outside world, or of the terrible ordeal that his mother has suffered.

It’s a riveting thriller buy Larson takes exception to the idea that Room is a harrowing watch; she insists it is an uplifting film about the mother/son bond.

"For me, it's a love story. It's about love, freedom and perseverance," she says. But the lengths she went to in order to prepare for the role certainly sound harrowing in themselves.

“I wanted to fully understand what it was like for Ma to be in ‘the room’ for so, so long. To simulate that, I stayed at home for a month and only left to go to the gym. I had very little connection to the outside world and I stayed out of the sun since Ma has not had sun on her skin in many years.”

Her self-imposed isolation brought back memories of her own childhood, she says, in particular the time her parents split up. “A lot of old memories resurfaced. I remembered a lot about my childhood that I had forgotten about. I was born in Sacramento but moved to Los Angeles with my mom and my little sister when I was seven. We moved into a studio apartment that was a little bit bigger than ‘the room’ – we had a door to a toilet so there was a little bit of separation there – but the bed came out of the wall.

“My mom couldn’t even afford Happy Meals but I remember it being one of the greatest times of my life. My mom has this incredible imagination and she instilled so much life into that space, so I never felt that I was lacking and I didn’t realise that we didn’t have anything.

“I also remembered all three of us asleep in the bed that came out from the wall, and waking up in the middle of the night to see my mom with her hands over her mouth trying to be quiet but sobbing uncontrollably. I didn’t realise until many years later that my father had asked for a divorce, which was why we had moved to Los Angeles.

“Sometimes you never fully understand why you are attracted to a project until you get deeper into it and that for me – and it’s giving me chills talking about it – was such a huge part of my life and I brought it to this film.” Larson has been working steadily since she was nine when she performed sketches on The Tonight Show with Jay Leno. During her teens she popped up on various TV shows and landed smallish roles in films including 13 Going on 30, Sleepover and Madison.

Articulate, smart and funny, she left high school at just 15. When Room premiered at the Telluride film festival, she considered wearing a T-shirt emblazoned with an Oscar to the press conference but then changed her mind. “I didn’t know if people would realise I was trying to be funny,” she says.

It’s certainly not a joke now. At 26, this newcomer has arrived and she could be picking up a real statuette very soon.