CocoRosie is a musical group formed in 2003 by sisters Bianca "Coco" and Sierra "Rosie" Casady. The sisters were born and raised in the United States, but formed the band in Paris after meeting for the first time in years. Their music has been called "freak folk", and incorporates elements of pop, blues, opera, electronica, and hip hop.

CocoRosie began as a duo, with Sierra singing, playing the guitar, piano and harp, and Bianca singing and manipulating various children's toys, electronic and percussion instruments, as well as other exotic noisemakers. They subsequently added various backing musicians, usually a bassist, keyboardist, and beatboxer. They have been a very active touring group, playing across Europe, the United States, and elsewhere. They have released four full-length albums: La maison de mon rêve (2004), Noah's Ark (2005), The Adventures of Ghosthorse and Stillborn (2007), and Grey Oceans (2010).

Sierra Casady was born in Iowa, and Bianca was born in Hawaii. When Sierra was about 5 years old and Bianca 3, their parents separated. The girls lived with their mother, Christina Chalmers, an artist and singer of American Indian and Syrian ancestry who grew up in Iowa. They moved to new towns almost every year, living in Hawaii, California, New Mexico, and Arizona. Because their mother believed that the girls would learn more doing art in the "real world" than in school, neither sister finished high school. Chalmers nicknamed her daughters "Rosie" (Sierra) and "Coco" (Bianca), from which the musical act takes its name.

Josh Werner (born September 17, 1974) is an American bassist, producer and songwriter. He was a co-writer and bassist of the Certified Gold RIAA albums Matisyahu (Live at Stubb's) and the Grammy nominated Matisyahu (Youth (Matisyahu album) album ).

Werner grew up in Milwaukee, WI. He was a student of Richard Davis. He is a member of Roots Tonic.

He is a frequent collaborator of American Record Producer Bill Laswell. As a session musician and producer, he has recorded with Wu-Tang Clan and Lee "Scratch" Perry. He also toured on bass with Freak Folk act Coco Rosie.

Werner is represented by notable entertainment lawyer Elliot Resnik.