Providing the voice for Brave’s Merida was a challenge for Kelly Macdonald, who normally relies on a subtlety that has helped her become one of our biggest stars

WHEN Kelly Macdonald was cast as schoolgirl Diane Coulston in his acclaimed film of Irvine Welsh’s Trainspotting, director Danny Boyle was taking a gamble on a teenager who was then working as a barmaid for a living.

Since that 1996 hit, her star has continued to rise with a series of high-profile roles. And yet all these years later, she finds herself playing a teenager again with her voice-acting debut in Disney-Pixar’s Brave – and admits that the role still comes easily to her.

Macdonald leads a predominantly Scottish cast including Billy Connolly, Kevin McKidd and Robbie Coltrane, bringing her Glaswegian tones to Princess Merida, the first heroine from the company behind Toy Story. She replaced Oscar-winning actress Reese Witherspoon, who had already recorded some of Merida’s lines.

“Merida is not your typical heroine,” says Macdonald, 36, who is one of Scotland’s biggest movie stars but remains as down-to-earth and likeable as she has always been. “I feel quite proud to be the voice of Pixar’s first female protagonist.

“Merida was such a fun character to play. The teenage aspect wasn’t a challenge – that came really quickly after 17 years. I amped up the teenage thing that’s never quite left my life. I just had to pretend my mum was in the room. Nothing winds you up like your parents.”

While Macdonald could easily relate to Merida’s teenage rebelliousness, she says she doesn’t share her sporting prowess.

“I would never get near a role like this in a live-action version, you know? I’m far too old, I’m not physical or athletic or beautiful enough, so thank goodness it’s an animated version.

“This was so far removed from me that if it was a live-action film, I don’t think I would even be in the casting!”

She adds: “It was an amazing experience and one I never thought I’d get the chance to do. I feel very privileged.

“I was totally blown away when I saw Merida for the first time. I just couldn’t believe what Disney-Pixar were capable of, and I couldn’t believe that I was given the gift to play this girl. It’s all pretty surreal still.”

Macdonald’s animated alter ego is the fiery and headstrong daughter of King Fergus (voiced by Connolly) and Queen Elinor (Emma Thompson).

The eldest of four children, Merida is an adventure-seeking tomboy, who would rather go for wild rides on her beloved horse Angus and practise her archery skills than live her privileged life.

Merida’s parents are intent on marrying off their daughter to the first-born son of one of the other clans, but the feisty teenager runs off, crossing paths with a witch (Julie Walters), whom she begs for help to change her fate.

Macdonald amended some of Merida’s lines after she was given the American-written script, but the biggest challenge lay in just using her voice to act.

“I’m the queen of subtlety when I’m working, but you can’t rely on any facial movements so it was really difficult for me. I always underplay everything but you can’t get away with that in animation. Everything had to be bigger.

“It was a real learning curve. In the end, it was really liberating and I was just enjoying myself.”

Macdonald – who has a four-year-old son, Freddie, with her husband, Travis bassist Dougie Payne, and is expecting the couple’s second child – is thrilled with what the film stands for: “Being a mother myself, the big message of Brave is brilliant – a mother makes some mistakes and apologises for them.”

She has come a long way since she picked up a flyer in a Glasgow bar and decided to try her hand and audition for Trainspotting. Long before Boyle was made responsible for presenting all the greatness and gallus guile of Great Britain at the opening ceremony of the Olympic Games, he spotted a touch of it in Macdonald and cast her as Diane.

It is rare that an actress’s very first role involves her being naked, bouncing up and down on an upcoming Scots star, but Macdonald played the part brilliantly and since then has more than proved herself adaptable.

Unlike Kevin McKidd, who was on holiday at the time, Macdonald was around when the iconic photographs of the various characters in Trainspotting were being taken and her scowl and wink became a key image of the 1990s. Yet while many young British actresses have tried and failed to crack America, Macdonald managed to do it by default.

She perfected a low Texan drawl for her key role in No Country For Old Men, for which she was nominated for a Bafta and it was this that opened yet more doors. Martin Scorsese was among those who detected hidden, untapped depths in her performance and cast her in the pilot episode of Boardwalk Empire, as a stubborn Irish girl who juggles her morals and her needs as a single mother after her abusive husband has been murdered on the orders of the uncrowned king of New Jersey, played by Steve Buscemi.

Her role in the HBO series has garnered critical acclaim but it has meant she’s had to live on the east coast of America for ten months of the year, with her husband and son. Yet it has paid off as in 2011 she was nominated for Best Supporting Actress in the Golden Globes. And a few days ago she announced that she was expecting her second child in December.

As she explained in a previous newspaper interview Macdonald didn’t have to work too hard at landing the lead female role in Boardwalk Empire. At the time her American agent just called up and asked her if she would be interested in doing an HBO TV series. As she has always believed that the script is the most important element of any project and not the star, she said that it would depend on the quality of the script. As she said previously: “I’ve done TV and I’ve done film, and I’m not snobby about it. It’s about the project. Then she said, ‘Well, one of the head writers from The Sopranos, Terence Winter, is doing this show, and Martin Scorsese is producing it and directing the pilot. It’s 1920s, Atlantic City…’” She didn’t know anything about the character they had in mind, but no matter – she was sold. There was no audition; she spoke with Winter over the phone, “and it was a done deal. It was just assumed that I would be doing it. And they were right to assume that!”

She next appears in Joe Wright’s Anna Karenina, alongside Keira Knightley, Aaron Johnson and Jude Law.

Thanks to her success across the pond, she now splits her time between her New York flat – where Boardwalk Empire is filmed -–and her Glasgow home. “I do feel really lucky. I still have to pinch myself quite often,” she says.

Boardwalk Empire is set to return for the third season in the autumn, but if she knows anything about what is in store for Margaret, Macdonald is keeping quiet. “I can’t give anything away but things don’t start well, I know that much. We’re halfway through season three and it’s not happy families.”

She’s hoping Scorsese, who sat in the director’s chair for the pilot, will return to direct another episode. “There are always rumours flying around that he’s going to direct another episode but it’s not happened yet. It would be amazing.”