MEMPHIS, Tennessee (AP) ― It was 1973, and Elvis Presley’s comeback was in fifth gear.

After years of making mediocre movies, he had returned to touring and performing in Las Vegas. In January of that year, he staged the “Aloha from Hawaii” concert live via satellite, viewed by a billion people worldwide.

But, due to a contractual obligation, he also needed to create new material. He and manager Col. Tom Parker decided that Presley’s beloved Memphis, Tennessee, was the place to do it.

The result was two recording sessions at Stax Records, the influential studio where Otis Redding, Isaac Hayes, Sam & Dave and others created the “Memphis soul” sound in the 1960s and early 1970s.

Presley’s sessions in July and December 1973 produced country, R&B and pop songs that were released in three separate albums.

Forty years after Presley’s Stax sessions, RCA Legacy is releasing the three-CD box set “Elvis at Stax: Deluxe Edition” on Tuesday. It’s the first time Presley’s songs recorded at Stax are together in the same release, which also includes outtakes and rare photos.

“The dissipation of the Stax recordings across three albums over 18 months provided little or no creative kudos for such deserving artistic accomplishment,” wrote “Elvis at Stax” producer Roger Semon in notes accompanying the release. “The objective of ‘Elvis at Stax’ is to reflect the true spontaneity and musicianship of Elvis’ sessions.”

The release of the set comes days before the start of Elvis Week on Saturday. Thousands of the singer’s devotees flock to Memphis each year for a celebration of his life and career, with a candlelight vigil serving as a memorial for his death, on Aug. 16, 1977, in Memphis at age 42.

Presley recorded his first song, “That’s All Right,” at Sun Studio in 1954. Fifteen years later, after making movies and staying away from the performing stage, he cut a series of hit singles at Memphis’ American Studio, marking the start of his comeback. Those hits included “In the Ghetto” and “Suspicious Minds.”