A man who recorded an album in his bedroom faces established acts such as Florence + The Machine, ex-Moloko star Roisin Murphy and Ghostpoet in the battle for the 2015 Mercury Prize.
Scottish composer Christopher Duncan, who performs as C Duncan, made Architect, his debut album, at his home in Glasgow.
His full-length record is amongst half of the debut albums that made the 12-strong shortlist for the albums of the year, which were unveiled on Lauren Laverne's BBC Radio 6 show.
He told Laverne: "It's absolutely amazing. I still can't believe it and I'm still pinching myself. I've known for a couple of days and it's been very difficult not to tell anyone."
Duncan, who counts fellow Glaswegian artist Charles Rennie Mackintosh amongst his influences, is classically trained.
"Having to sing vocal after vocal and layer after layer was the most time-consuming bit," he added.
Meanwhile, Irish-born producer Aphex Twin - Richard David James - is set for mainstream recognition after being underground for a quarter of a century after his sixth album Syro made the list.
Florence Welch and former winner Jamie xx are already the bookmakers' favourites after Florence + The Machine's third album How Big, How Blue, How Beautiful and Jamie xx's second solo album In Colour received nominations.
Jamie xx, 26, said: "It was such a big thing for The xx before when we got nominated, and it felt very surreal that first time."
The singer, who triumphed in 2010 with The xx's debut album, added: "It's wonderful to be nominated again. It was extremely stressful to win, the tension in the room - and I got to hide behind the others when they did the speech."
Murphy's third album Hairless Toys also made the shortlist, alongside Shedding Skin, the third album from Ghostpoet.
Murphy told Laverne: "It just feels great, it's wonderful."
Former Supergrass frontman Gaz Coombes also landed a spot on the list with his second solo album, Matador.
Coombes said: "It's insane. I am still in shock, it hasn't sunk in yet. I made this mad album last year in my basement. When Matador was finished, I knew it was a cool record but you never know how it's going to come across to people.
"I'm pretty overwhelmed. It's been such a mad year."
Debut albums that made the 12-strong shortlist include Wolf Alice's My Love Is Cool, Eska's eponymous record, Benjamin Clementine's At Least For Now, Are You Satisfied? from Kent punk pair Slaves and Before We Forgot How To Dream by Northern Irish singer SOAK.
Clementine, 26, said: "I didn't expect anything because this is my first album, but I've had really nice reviews from different journalists and people are listening to my music. I'm really surprised."
The Mercury Prize shortlist was narrowed down from over 290 albums by a judging panel. The awards, to be hosted by Laverne, will be held at the Radio Theatre at Broadcasting House in London on November 20.
Laverne said this year's shortlist is "the perfect snapshot" of British music in 2015, adding: "It's the perfect snapshot of where music is right now and where it might be heading in the future."
Simon Frith, chair of judges, said: "This year's Mercury Prize shortlist includes seven debut albums and it celebrates artists from every stage of their careers.
"These musicians come from a fascinating variety of musical places, cultures and histories. What they have in common is the ambition and the craft, the ideas and the imagination to make great music."