IT takes courage to go up against TV’s titan Downton Abbey, but Lacey Turner is up for the challenge, as Our Girl returns to screens, ready to battle it out in the Sunday evening ratings war.

Following its success as a one-off drama last year, she’s simply excited to be reprising her lead role as Molly Dawes.

“I can’t believe how successful the last one was.

To go from something so small, which was really important to us, and to be given a five-part series is just amazing,” says 26-year-old Turner.

“I love Molly. She’s feisty, disobedient and passionate, which I think is what draws me to her.

She wants to belong and do better and help. I think maybe, in her life, she hasn’t really been given the opportunity.”

In the first airing, Molly, born and raised in East London and facing few prospects, decided to join the Royal Army Medical Corps.

Now, the series begins with her being deployed to Afghanistan as a serving medic.

“There are moments when she’s really struggling and doesn’t know quite what to do, which I think would be the case for a real soldier.

It’s nice to see her go on a different journey and mature as a person,” says Turner, known to millions as EastEnders’ Stacey Slater/Branning, a role she reprised in August, after leaving the soap in 2010 and making a brief appearance earlier this year.

Molly’s relationship with her family remains as strained as ever. “They haven’t changed. They’re still nuts, with far too many kids in one house,” explains the London-born actress.

“Molly and her dad’s relationship is not the greatest, and as a family, they find it hard to communicate with one another.

“To join the Army, she’s got the perfect opportunity to become part of a team and a family, to achieve something and feel like she belongs somewhere.”

As one of the last missions before the British Army withdraws from the country, Molly is thrilled to be joining the platoon, even if they don’t welcome her with open arms.

“They’re a team who’ve been working together for six months and they spend all day, every day, with each other, so I suppose you have to earn your way in, and that’s what she tries to do.”

That includes trying to impress their leader Captain James, played by Lark Rise To Candleford’s Ben Aldridge.

“Molly thinks he’s amazing, has a huge amount of respect for him and looks up to him,” says Turner. Those feelings aren’t reciprocated, and things only get worse when Molly discovers that Smurf (Game Of Thrones’ Iwan Rheon), a face from the past she’d rather forget, is also a member of the platoon.

“They don’t start off too well,” she adds. “He’s a bit mean actually, but throughout the series, they develop a really good bond and look after each other, and I think they have a really comforting relationship.”

Captain James also warms to her, so it becomes “very much a love triangle”, Turner reveals, laughing.

As Molly feels the pressure to prove herself, a growing friendship with a local Afghan girl puts her in a precarious position, with more than just her reputation in jeopardy. But Turner, who briefly attended the Sylvia Young Theatre School and won her first of four British Soap Awards at the age of 17, argues that Molly is in danger throughout the whole series.

“Anyone who’s on the front line is in danger. The people who do this for real are so amazingly brave. I jump when a gun goes off, so you can’t even imagine what it’s like to have bullets flying past your ears” she says. “How men do it amazes me, but there are so many girls my build and size.

The kit alone is so uncomfortable to move in. I felt like a tortoise or a donkey.”

She laughs when asked if she was in the best shape of her life. “No,” she exclaims. “I put so much weight on, I didn’t stop eating!”

That’s despite spending her days running up and down mountains, wading through rivers and hanging out of helicopters. “I loved that, it was exciting. I’d never done stuff with loads of action in it,” says the actress, who starred in the supernatural dramas Being Human, Bedlam and Switch, as well as the improvised True Love during her EastEnders hiatus.

The medical terminology didn’t faze her, nor the prosthetic injuries (“I’m not squeamish and love bones sticking out!”), or even the threat of snakes. It was the crickets that rattled her.

“They were everywhere,” she recalls, shuddering. “We had a long talk about snakes but we didn’t see one – but I did have a few fights with crickets.”

She admits she found the three-month shoot physically and mentally exhausting. Every two weeks they were given three days off; she made the most of her free time to explore the region, bar the famous vineyards. “I don’t drink, so I left that to the drinkers.”

With the shoot behind her, and the transmission date imminent, she just hopes the soldiers who’ve inspired the story salute the series.

“You feel pressure to get it right, because what they do is so amazing. I don’t want to disappoint them, really. If it was only the soldiers who sat down and watched it, and were happy with it, then that would be enough for me,” says Turner.

“It matters, because these people do this for real and you want to try to do them as much justice as you can. I hope we have.”

  • Our Girl begins on BBC1 tomorrow