Musician and songwriter Leon Russell has died in his sleep at the age of 74, according to a post on his official Facebook page.

Born in Lawton, Oklahoma on April 2, 1942, Russell first achieved widespread recognition as a member of Delaney & Bonnie and Friends, and then through his collaborations with Joe Cocker. He co-produced Cocker’s hit self-titled 1969 album, and wrote two of its songs. Russell then assembled and joined the band for Cocker’s famed Mad Dogs and Englishman tour, which spawned the Russell co-write “Superstar.”

During that trek, Russell’s own self-titled solo album was released, containing his signature track, “A Song for You.” In the following years he had his biggest chart successes with 1972’s “Tight Rope” and 1975’s “Lady Blue.” He also worked as a producer, songwriter, studio collaborator and touring partner for artists such as the Rolling Stones, Freddie King and Bob Dylan.

After years of relative obscurity, Russell was brought back into the spotlight by longtime fan Elton John, with whom he teamed up for the 2010 album The Union. After touring together with John in support of that album, and releasing a documentary chronicling their collaboration, Russell released his final solo album, Life Journey, in 2014.

In July of this year, Russell suffered a heart attack, but was expected to make a full recovery. The cause of his death is as yet unknown.