WaterTower Music will release a new version of the song The Rains of Castamere from the HBO original series Game of Thrones. The show’s fourth season will feature a version of the song by the Icelandic band Sigur Rós. The track is written by the composer of the series, Ramin Djawadi and features lyrics by George R.R. Martin. The song will be released digitally on April 13, 2014 and is now available for pre-order on Amazon. Check out an audio clips from the track after the jump. The Rains of Castamere has previously appeared numerous times during the first three seasons of the show, including in a version performed by The Nationals, which was featured on the Season 2 soundtrack album. Game of Thrones will return for its fourth season this Sunday, April 6 on HBO. For updates on the series, visit the official show website.