Michelle Keegan has loved the challenge of making BBC One's Our Girl but, after four years, she's saying goodbye to the role. Georgia Humphreys hears how playing Georgie Lane has changed her for the better.

Michelle Keegan has learnt some huge life lessons from her four years in Our Girl.

The 32-year-old, who was born in Stockport, has had to spend months away from home filming the much-loved BBC One series.

"I believe I've grown throughout this job - as a person, as an actor," says the former Corrie star, who plays medic Georgie Lane in the army drama.

"You're away from your family and your friends for such a long time, and it makes me realise that I am strong, and I can cope."

Keegan - who's married to TV personality Mark Wright (who first found fame on The Only Way Is Essex) - headed to South Africa for four months to shoot the new episodes of Our Girl.

It's the fourth series, and is set one year on from military unit 2 Section's last tour in Bangladesh. Georgie is now working in England, has been promoted to a sergeant and is training in mentoring, a job she's enjoying focusing on.

Then 2 Section needs to go back to Afghanistan, and they ask her to go.

"And she says, 'No, no, I'm happy where I am'; she's training up a girl called Mimi who was going to take her place as a female medic," explains Keegan, who's bubbly and down-to-earth, greeting all the journalists with a hug.

"Anyway, there's an altercation, and she sees how Mimi reacts. She's not 100% happy with it because she feels like she has to go out and mentor her in Afghan."

However, there's perhaps more behind Georgie's decision than meets the eye.

Fans will remember how, in series 3 (which was split into two parts), her fiance Elvis (played by Luke Pasqualino) was killed in Afghanistan.

He was blasted from a rooftop in Kabul by a hidden bomb, and then died in Georgie's arms. It was heart-breaking to watch.

Keegan suggests that going back out into the field is "Georgie's way of trying to get closure on Elvis's death".

And, as the series goes on, the star adds we will see her suffering from PTSD.

"A few years ago I had a meeting with female medics who have seen their mates dying in front of them.

"And all they want to do is go back into the army. They don't want any time off."

So, she thought it was a very relatable storyline to explore.

"I think Georgie threw herself into work and pretended nothing happened," she elaborates.

"This time, we need to explore that a bit more, because that's not real life - you can grieve for years.

"Georgie's got a way of brushing things under the carpet, and I think that's what she's been doing."

As well as taking on emotional storylines, Keegan says the physical side of this show never gets any easier.

"As soon as we get to South Africa, we have a boot camp, where we do drills, patrolling, running...

"We have to adjust to the heat. Obviously we can't just have a light bag on the back because it would just look silly, so we have to have the full kit in a bag. And the weapons are really heavy as well."

Although she professes she loves a challenge, she admits there are moments when she finds herself thinking, 'I can't do this'.

For this series, there was a particularly scary stunt - which we see right at the beginning of the first episode - where she had to hang upside down in a car.

"I'm scared of heights - that wasn't great, because it's like a jeep and they spin it on a wheel and it's quite high.

"It feels like you're upside down forever, and you have to unclip yourself.

"I panicked, I couldn't unclip the clip, so I remember looking at Rolan (Bell), who plays Kingy, and he helped me out."

The star - who's also known for ITV drama Tina And Bobby and Sky comedy Brassic - is keen to do different kinds of roles in the future.

She shares that her next project, which can't be named yet, is being filmed in the UK, so this year she'll be working at home - something she's clearly happy about, a grin on her face.

However, leaving the role of Georgie was a really difficult decision.

On her last day of filming, the cast who play the rest of 2 Section had already gone back to the UK. So, she said goodbye to Georgie on her own, and had a little cry.

Asked what she will miss most, she muses: "I'll definitely miss the camaraderie, being in a group. When you're away for such a long time, you do become a family. Honestly, you become so close.

"But mostly I'm just going to miss the role of Georgie. I love playing such a strong female, and Georgie is an amazing role model for girls and women out there."

She feels she has a little bit of Georgie in her now, in the way she is much calmer and less prone to panicking than before she played her.

This particularly came in handy when, a few years ago, she saw a woman faint in a restaurant. She'd ended up lying face down in her plate.

"I didn't have to give them CPR or anything, but obviously I checked her airways," she recalls.

"I remember she had started to come around, so I sat her down, I kept her really calm, told her husband to get a drink for her. And I wouldn't have known to do that if it wasn't for this show."

Keegan only joined the cast in 2016. In the pilot and first series, EastEnders' Lacey Turner played the lead role (Molly Dawes, who was also a medic deployed to Afghanistan).

The question is, who will be the next Our Girl star?

"I think whoever gets this role is really lucky, because it is an amazing job," says Keegan.

"It is really intimidating, this job - I was really intimidated when I first started.

"But I think you just have to throw yourself into this role, and when you do that, you really start enjoying it."

Our Girl returns to BBC One on Tuesday March 24