Marty Balin, frontman of 1960s hippie rock legends Jefferson Airplane, has died.
He was 76 when he died on Thursday, Rolling Stone reports. The cause is not yet known.
Balin formed the progressive group in 1965 alongside guitarist Paul Kantner. He was originally the sole lead singer, and was soon joined by Grace Slick.
Their songs 'White Rabbit' and 'Somebody to Love' were representative of the late '60s counterculture, and both featured in Rolling Stone's top 500 songs of all-time list, published in 2004.
When the band split in half, Balin sided with the members - including Slick - that formed Jefferson Starship. He left the group in 1978 for a solo career, occasionally getting back together with his old bandmates.
He was inducted into the Rock and Roll Hall of Fame in 1996 with the rest of Jefferson Airplane.
In a statement, the band said Balin "helped start a revolution that still lives on today. He will be greatly missed - our hearts go out to his family, friends and music fans everywhere."
Balin had open-heart surgery in 2016 after complaining of chest pains, but it's not known if this is related to his death.