Jimmy Ellis, 74, of the Trammps

Jimmy Ellis, 74, lead singer of the Philadelphia rhythm and blues band the Trammps, whose hit "Disco Inferno" was featured in the 1977 movie Saturday Night Fever, died Thursday, March 8, in Rock Hill, S.C., from complications of Alzheimer's disease, according to his daughter, Erika Stinson.

Mr. Ellis grew up singing in church in Rock Hill before moving to the Philadelphia area, where he worked as a chauffeur and gardener. He also sang in bands like the Moods and the Exceptions, which scored a doo-wop hit in 1962 with "Down by the Ocean" on the Cameo-Parkway label.

The Trammps came together in the early 1970s, featuring members of the Moods and the Volcanos, and included Earl Young, the "velvet hammer"-wielding drummer for the Philadelphia International Records house band known as MFSB.

Young, a bass, sang the Trammps' first hit, a doo-wop version of "Zing! Went the Strings of My Heart." After that, Mr. Ellis sang lead on all the group's hits, including "Love Epidemic" and "Where Do We Go From Here?"

Mr. Ellis sang in a commanding, gravelly baritone that he unleashed with particular force on the "Burn, baby, burn!" exhortations of "Disco Inferno," which was originally included on an album of the same name released on Atlantic Records in 1976. The song was used in a John Travolta dance showcase scene in Saturday Night Fever. The sound track was the biggest-selling album of all time until Michael Jackson's Thriller, released in 1982, eclipsed it.

"Jimmy was straight out of church," singer Bobby Eli, the guitarist who was a founding member of the Trammps and who played on all of the group's recordings, said in an interview Friday. "The church never left him. And even for a church singer, he was unique. He had a scream on him that couldn't be touched. He was the voice of the disco era for the Sound of Philadelphia, but he never wanted to be a disco singer. He considered himself a rhythm-and-blues singer."

The Trammps broke up in 1980. Mr. Ellis gave up pop music for a time and moved back to South Carolina, concentrating on gospel music. But he eventually returned to touring with the Trammps, working steadily through 2010.

In addition to his daughter, Mr. Ellis is survived by his wife, Beverly; a son, Jimmy; and eight grandchildren. A memorial service was scheduled at the Central Church of God in Charlotte, N.C., for Friday, March 16.