More than 100 festival-goers have taken to the main stage at Latitude as part of a performance put together by celebrity choirmaster Gareth Malone.
The group of audience members, who ranged in age from children to pensioners, were selected ahead of this year's festival and spent just three days rehearsing together.
Choir members were drawn from all over the country - and one even travelled from Abu Dhabi to join the show.
Taking to the stage at Henham Park, Suffolk, this afternoon, Malone said: "While you've all been sunning yourself and enjoying Latitude, these 115 people from the Latitude audience have been rehearsing and learning their parts.
"They're here to entertain you for this 10th anniversary festival and it's really a quite special thing - the audience has taken over the stage.
"I feel incredibly blessed to work with such a great group of people."
Malone found fame with his television programme The Choir, which introduced new participants to singing, but he is perhaps most famous for his work with the Military Wives Choir.
Members of the Latitude choir were invited to apply online and had to submit a recording of themselves singing as well as a run-down of their past musical experience.
Among the choir was journalist Carrie Fitton, 57, from Bury St Edmunds, Suffolk.
She began singing as a child and has performed with various choirs.
She said: "The choir is a complete mixed bag of people from all over the country and the atmosphere has been really friendly.
"Gareth is stunningly good at getting everybody feeling they're doing a great job, getting the right phrasing and he's such a good motivator.
"He is very humorous and puts you at ease, but is also very professional."
Amy Davies, 14, from Needham Market, Suffolk, was also in the choir. Her parents Amanda and David were in the crowd.
Mr Davies said: "She is in the school choir but has never done anything on this scale before and there's a big crowd so I'm sure she'll be feeling the nerves.
"We're very proud of her and she has got so much out of working with Gareth."