Fleet Foxes' debut album reached number 3 in the UK album charts
Fleet Foxes have been announced as headliners of the 2011 Green Man Festival in the Brecon Beacons.
The Seattle-based folk band will be at the three-day event at Glanusk Park, Powys which starts on Friday 19 August.
The band came to prominence in 2008 with the release of their second EP, Sun Giant, and their debut full length album Fleet Foxes.
Other acts booked for this year's event include Bellowhead, Robyn Hitchcock, and Villagers.
Founded in 2003, Green Man has become one of the most popular alternative festivals.
In 2010 it won the best medium-sized event at the UK Festival Awards.
A Green Man spokesman said: "Fleet Foxes have come up time and time again as a band that people want to see at Green Man, and here at the festival we're massive fans, so we're absolutely delighted that they'll be gracing our main stage this year."
Fleet Foxes' debut album reached three in the UK album charts in 2008 and their second album, Helplessness Blues is due to be released next May.
Bellowhead have won Best Live Band at BBC Radio Two's Folk Awards
The quintet describe their music as 'baroque harmonic pop jams'.
Also appearing in 2011 are Villagers, whose debut album, Becoming a Jackal, was nominated for the 2010 Mercury Award.
Among the other prominent acts booked for the festival are Bellowhead, an 11-piece outfit who have been voted Best Live Band at the BBC Radio Two Folk Awards five times.
Also booked for the event is a former member of The Soft Boys, Robyn Hitchcock, who has played with the likes of Nick Lowe, Gillian Welch, Graham Coxon and REM's Peter Buck over a varied 30-year career.
Other acts appearing at this year's event include The Burns Unit, The Ramshackle Union Band, The Gentle Good, and Emily Barker.
Last year's festival sold out ten weeks in advance of the festival with an attendance of about 10,000 people.
Previous headliners in the festival's eight year history have included ex-Led Zeppelin frontman Robert Plant, Welsh band Super Furry Animals, Jarvis Cocker, The Doves and Badly Drawn Boy.
Two more headline acts for Green Man 2011 will be announced by festival organisers later this year.