Rock and Roll Hall of Famer Leon Russell Passes Away at 74

Notable singer and songwriter Leon Russell passed away Sunday in Nashville. He was 74.

Russell's wife, Jan Bridges, said that he died in his sleep, according to a statement on his website.

In a later statement obtained by ABC News, she added in part, "He was recovering from heart surgery in July and looked forward to getting back on the road in January. We appreciate everyone's love and support."

Earlier this year, Russell had to postpone 28 concerts between July and September after suffering a heart attack.

Still, his website said then in a statement that the Rock and Roll Hall of Famer was "optimistic" and able to make a complete recovery.

In the 1960s, Russell made a name for himself as an in-demand session keyboardist. He was part of the Wrecking Crew, a famed collective of studio musicians.

Russell also established himself as a songwriter. Some of the best-known songs that he wrote are "Delta Lady," "Superstar," "This Masquerade" and "A Song for You." His solo career scored him Top 20 hits, including his 1972 single "Tight Rope" and 1975's "Lady Blue."

He also collaborated with artists such as Joe Cocker and Delaney & Bonnie, and toured with Edgar Winter, The New Grass Revival and Willie Nelson.

In 2010, Russell collaborated with Elton John -- a longtime admirer of Russell's -- on his acclaimed album "The Union."

On "Good Morning America," John said of Russell, "He was my biggest influence as a piano player, a singer and a songwriter."

The following year, in 2011, Russell was inducted into the Rock and Roll Hall of Fame.