‘I’M really excited,” says Nina Nesbitt. “This is my first time playing TRNSMT. I’ve played T In The Park three times and every one of them was among my favourite gigs - there was always such a great crowd.”

Heading the King Tut’s Stage at TRNSMT on July 8, the Balerno-raised singer-songwiter says she plans to play a set of crowd-pleasers from her 2014 debut album Peroxide as well as material from her forthcoming LP, due for release later this year.

“The new album is almost done and I’ve had three singles out so far from it, so I’ll definitely play them,” says Nesbitt, referring to last year’s summer hit The Moments I’m Missing and follow-up The Best You Had, an r’n’b-swinging kiss-off to a complacent love which became her most streamed track yet on Spotify.

In March this year Nesbitt joined Sasha Sloan and Charlotte Lawrence for the sassy Psychopath, the first Spotify Single collaboration to mark Women’s History Month.

In the next few weeks and months, she plans to follow third single Somebody Special – an elegant, sophisticated track which is the embodiment of what she describes as “suburban pop” – with another new album cut, Colder.

There will also be material released, she says, from her recent work with DJs, though she’s not naming names as yet.

Nesbitt started songwriting at the age of 10, a time when the youngster’s passion for music was rivalled with a talent for rhythmic gymnastics. She ended up in the Scottish team and training for the Commonwealth Games, and credits the sport for giving her a sharp sense of drive. At the age of 15, then competent at the piano, guitar and the flute, she heard Taylor Swift’s song 15. The gymnastics were given the heave-ho.

“I remember ... being like: ‘Oh my god, it’s a girl with a guitar writing her own songs,’” she told a recent interviewer. “I wanted to do that. I don’t come from a musical background or a wealthy background, so I needed to find a way of getting out there and that thing of writing your own songs felt affordable and doable.”

That way was uploading songs she had written in her bedroom to YouTube, a potentially terrifying prospect for a young musician starting out. The rough and tumble of unleashing your songs to the world for all to comment on, critique and criticise served her well, however.

By the time she met Ed Sheeran in 2011, she had enough confidence to perform a song for him, and was offered support slots on his European tour. A record deal with Island followed, as well as a string of Top 40 singles, high-profile covers of songs by the likes of Example, John Newman and – for a John Lewis ad campaign – Fleetwood Mac.

Having worked in the past with English country duo The Shires and LA singer Goody Grace, Nesbitt says she’s keen to team up with other artists in the future.

“Now more than ever I’m open to collaborations,” she tells The National. “More and more artists are coming together and working together nowadays and I love working with other people.

“My end goal is working with Calvin Harris because I think his collaborations are always so, so very good. I really love what he does, and obviously he’s another Scot, so I’d love to collaborate with him.”

Perhaps this openness is partly due to Nesbitt’s recent time between record deals. Now signed to long-established independent Cooking Vinyl, she wrote material intended for other people when her deal with Island came to an end.

Writing from Niightwatch, her studio at home in London, the experience liberated her from preconceptions she’d imposed upon herself.

“A lot of this album I kind of wrote by accident,” she explains. “I would write songs and not really think they were for me. When I would be playing them in session or at home, it wasn’t like: ‘I’m going to make an album with this person’, it was more I thought the song might be for that other person. It felt really easy and very natural.”

She continues: “I always try to write the best song I can write. But you write in a different way when you’re not thinking about yourself. There’s always a part of me that’s like: ‘Hmm, pop music. Pop music isn’t cool.’

“I love pop music, though I do worry, especially coming from a singer-songwriter background, if a song is too pop for me or whether I would say a particular lyric.

“But when you’re writing for other people you’re not thinking about all that, you’re just trying to write a song that you love. And at the end of the day I’m not really cool so it’s fine.”

A star of indie-pop in the arena-sized, international hit-making sense, Nesbitt produced much of the record herself.

Some material was worked on with Red Triangle, the production duo behind hits by James Arthur, Little Mix and The Vamps, and Jordan Riley and LostBoy, two young writer-producers also based in London.

The latter was discovered by Fraser T Smith, another contributor to Nesbitt’s new album.

The producer of Stormzy’s recent Brit Award-winning Gang Signs & Prayer album and Adele’s hair-billowing 2011 mega-ballad Set Fire To The Rain, Smith’s work has been long appreciated by Nesbitt.

“He did one of Craig David’s early albums and it’s been really cool to work with him,” she says.

Nesbitt has spent much of the year so far touring across the US, and is currently back there ahead of her set at TRNSMT. Following the July 8 date on Glasgow Green, she plays a number of UK festivals before joining fellow TRNSMT performer Lewis Capaldi on tour later this year.

“I’ve been basically living out of a van since the start of the year, I’ve been so busy,” she says. “I guess in this industry you can be so busy one minute, and then there’s nothing. So when you’re busy, you just have to roll with it.

“Because every release is international, you have to visit all these places and as America is so big, you literally have to be there for a year before you get any sort of results. So I’ll go back out there again after the UK festivals.”

She’s got a day to herself on July 11 – the day she turns 24.

“I’m actually going to celebrate it at TRNSMT,” Nesbitt says. “It’ll be the best party ever.”

Nina Nesbitt plays TNSMT on July 8. www.trnsmtfest.com ninanesbittmusic.com

Five-day festival TRNSMT is headlined by Stereophonics (June 29), Liam Gallagher (June 30) Arctic Monkeys (July 1), Queen + Adam Lambert (July 6) and The Killers (July 7). www.trnsmtfest.com