The Eden Project has announced a full line-up of special guests for the Sigur Rós Eden Session on June 30, headed by indie-folk trio Daughter and New York country-folk singer Willy Mason.

London-based Daughter, otherwise known as Elena Tonra, Igor Haefeli and Remi Aguilella, are fresh from releasing their debut album If You Leave, whose singles Smother and Still have both been playlisted on BBC Radio 1, 6 Music and XFM.

Daughter mix Elena’s haunting lyrics with sparse musical arrangements to create an intimate, melancholy sound. If You Leave hit number 16 in the UK album charts and number four in the UK indie album charts.

Willy Mason is a country folk singer from the Massachusetts island of Martha’s Vineyard. His most recent album, Carry On, was released in December last year (2012) and followed his 2005 debut Where the Humans Eat and 2007’s If the Ocean Gets Rough.

Notable singles include Oxygen and We Can Be Strong, featuring previous Eden Sessions headliner KT Tunstall, which played in the first series finale of Channel 4’s Fresh Meat.

The main stage line-up for the evening is completed by Californian psychedelic electropop outfit Mwahaha and Dawn Chorus Ignites, an instrumental shoegaze collective who recently released their third EP Take Me With You.

The Mediterranean Biome stage will feature London folk troubadour Luke Sital-Singh, singer-songwriter Thomas J Speight, Dorset folk rockers Saturday Sun and haunting Cornish folk singer West Barbary.

The acts join acclaimed Icelandic post-rock band Sigur Rós, whose Eden show is one of just a handful they will play in the UK this summer. Sigur Rós have recently released Brennisteinn, the first single from their forthcoming album Kveikur, which is due to be released on June 17, two weeks before their Eden date.

Rita Broe, Strategic Marketing Director at the Eden Project, said: “This is a very exciting, eclectic support line-up which will sound great ahead of Sigur Rós taking to the stage for their headline set.

“Daughter have won a lot of fans in the past year and their excellent debut album broke the top 20 last month. We’re very excited to have them at Eden on the cusp of what promises to be a big career.

“Willy Mason, who has toured with Ben Howard and Mumford & Sons, is one of the best contemporary country singers out there and we’re delighted to welcome him to Eden."