James “Jim” Gilstrap, a singer whose credits include the Good Times theme song and Stevie Wonder‘s “You Are the Sunshine of My Life,” has died. He was 79.

Gilstrap’s nephew and family spokesperson, Geoffrey “Geoff Gil” Gilstrap, said he died Saturday from natural causes.

Gilstrap sang the song for Good Times, which ran from 1974-79, with Blinky Williams. The catchy, gospel-tinged tune (“Keepin’ your head above water/Making a wave when you can”) was composed by Dave Grusin with lyrics by Alan and Marilyn Bergman.

Gilstrap was a featured vocalist with Stevie Wonder’s Wonderlove and contributed to many of the singer’s recordings. He sang the first two lines of Wonder’s “You Are the Sunshine of My Life” (“You are the sunshine of my life/That’s why I’ll always be around”). Singer Lani Groves sang the next two lines (“You are the apple of my eye/Forever you’ll stay in my heart”) before Wonder’s vocals kick in, with Gilstrap and Groves continuing to sing backup. The song, from Wonder’s 1972 album Talking Book, won the Grammy Award for best male pop vocal performance.

Gilstrap also worked on Wonder’s albums Wonderlove and Innervisions. 

In 1975, he signed a recording contract with Chelsea Records and released a single, “Swing Your Daddy” that reached No. 4 on the U.K. Singles Chart and No. 10 on the  U.S. Billboard Black Singles chart. The song peaked at No. 64 in Australia. He released an album, Love Talk, in 1976.

Throughout his career, Gilstrap also collaborated with Quincy Jones, Michael Jackson, The Jacksons, Aretha Franklin, Anita Baker,  Whitney Houston, James Ingram, George Benson, Bill Withers, Gladys Knight, Luther Vandross, Patti LaBelle, Kenny Loggins, Dolly Parton, Teddy Pendergrass, Stanley Clarke, Boz Scaggs and others.

“Jim was one of the most respected session vocalists of his generation, bringing his powerful and soulful voice to countless recordings that helped define the sound of popular music,” his nephew said.

Born Nov. 10, 1946, Gilstrap was the last surviving member of a family of 10 siblings. He is survived by his wife, Gloria, and his children.