Leon Russell has died at age 74. According to his official website, his wife said he passed in his sleep. Russel was a musician's musician, an in-demand sideman and session player, working with everyone from Jerry Lee Lewis, Glenn Campbell, Phil Spector, Herb Alpert, The Rolling Stones, and was a member of Joe Cocker's Mad Dogs and Englishmen tour. He was a successful solo artist in the '70s, reaching #2 with "Tightrope" from 1972's Carny.

Russell faded from the spotlight and suffered a string of health problems in the '00s, but was coaxed out of retirement by Elton John for 2010's acclaimed The Union (and subsequent tour). Elton paid tribute to Leon on social media early today, writing, "My darling Leon Russell passed away last night. He was a mentor, inspiration and so kind to me. Thank God we caught up with each other and made The Union. He got his reputation back and felt fulfilled. I loved him and always will."

Rest in peace, Leon. Your musical legacy lives on.