Title: If This World Were Mine
Content:  Fifteen years after the original recording, Luther Vandross and Cheryl Lynn re-recorded it for her album Instant Love and made the song a R&B top five smash peaking at number four in 1982 on the Billboard Hot R&B Singles chart.
Title: If This World Were Mine
Content:  A decade later, Coko of SWV and rising R&B singer and Tyrese recorded it for her 1999 solo album Hot Coko. The song is featured on John Legend's 2004 live album Solo Sessions Vol. 1: Live at the Knitting Factory, with Imani Uzuri singing the female lead. In 2005, Alicia Keys and Jermaine Paul recorded it for the Luther Vandross tribute album So Amazing: An All-Star Tribute to Luther Vandross. The song was nominated Best R&B Performance by a Duo or Group with Vocals at the Grammy Awards. They did not win; instead, the Grammy was awarded to Beyoncé Knowles and Stevie Wonder for their cover "So Amazing," which appeared on the same Vandross tribute album. In 1973, Jerry Butler and Brenda Lee Eager recorded the song on their album "The Love We Have, the Love We Had."
Title: Luther Vandross
Content:  songs were covers of original music by other artists such as "If This World Were Mine" (duet with Cheryl Lynn), "Since I Lost My Baby", "Superstar", "I (Who Have Nothing)" and "Always and Forever". Duets such as "The Closer I Get to You" with Beyoncé, "Endless Love" with Mariah Carey and "The Best Things in Life Are Free" with Janet Jackson were all hit songs in his career. During his career, Vandross sold over 40 million records worldwide, having eleven consecutive Platinum albums a record achieved by a R&B artist at the time and received eight Grammy Awards including Best Male R&B Vocal Performance four different times. He won a total of four Grammy Awards in 2004 including the Grammy Award for Song of the Year for a song recorded not long before his death, "Dance with My Father".
Title: If This World Were Mine
Content:  "If This World Were Mine" is a 1967 song by soul music duo Marvin Gaye and Tammi Terrell from their album United. Written solely by Gaye, it was one of the few songs they recorded without Ashford & Simpson writing or producing. When it was released as a single in November 1967 as the B-side to the duo's "If I Could Build My Whole World Around You", it hit the Billboard pop singles chart, peaking at number sixty-eight, and peaked at number twenty-seven on the Billboard R&B singles chart. Gaye would later put the song into his set list during his last tours in the early-1980s as he performed a medley of his hits with Terrell. The song was covered a year later by Joe Bataan on the 1968 Fania Allstars LP Live at the Red Garter, Vol. 2, and in 1969 by Ambrose Slade (pre-Slade) on their album Beginnings.
Title: The Best of Luther Vandross... The Best of Love
Content: "If This World Were Mine" is a Marvin Gaye & Tammi Terrell cover (1967) ; "A House Is Not a Home" is a Dionne Warwick cover (1964) ; "Since I Lost My Baby" is a cover by The Temptations (1965) ; "If Only for One Night" is a Brenda Russell cover (1979) ; "Creepin'" is a Stevie Wonder cover (1977) ; "Superstar" is a Delaney & Bonnie cover (1969) ; "Until You Come Back to Me (That's What I'm Gonna Do)" is an Aretha Franklin cover (1973) ; "Love Won't Let Me Wait" is a Major Harris cover (1975) Notes
Title: The Ultimate Luther Vandross
Content: 1) "Give Me the Reason" (Luther Vandross, Nat Adderley Jr.) – 4:45 (From the Motion Picture Soundtrack Ruthless People) ; 2) "Never Too Much" (Vandross) – 3:50 (From Never Too Much) ; 3) "If This World Were Mine" (Duet with Cheryl Lynn) (Marvin Gaye) – 4:00 ; 4) "A House Is Not a Home" (Burt Bacharach, Hal David) – 7:08 (From Never Too Much) ; 5) "Don't Want to Be a Fool" (Vandross, Marcus Miller) – 4:34 (From Power of Love) ; 6) "So Amazing" (Vandross) – 3:41 (From Give Me the Reason) ; 7) "Til My Baby Comes Home" (Vandross, Miller) – 3:59 (From The Night I Fell in Love) ; 8) "There's Nothing Better Than Love" (Duet with Gregory Hines) (Vandross, John "Skip" Anderson) – 4:17 (From Give Me the Reason) ; 
Title: Instant Love
Content:  Instant Love is a 1982 album by American singer Cheryl Lynn, released on Columbia Records. Luther Vandross produced the album and also performed a duet with Lynn on "If This World Were Mine", a cover of the original recording by Marvin Gaye and Tammi Terrell. The arrangements were by Luther Vandross, Marcus Miller and Nat Adderley, Jr. The album peaked at #7 on the R&B album charts and #133 on The Billboard 200. Coming off of his success with Aretha Franklin's "Jump to It," Cheryl and Luther delivered the title cut as a first single, but it only reached #16 on the R&B charts. The two artists did however make an impact with their duet on a remake of the Marvin Gaye & Tammi Terrell classic "If This World Were Mine" which became the biggest hit (#4 R&B) off of this album. A third single, "Look Before You Leap", stalled out at #77 on the R&B charts.
Title: If This World Were Mine
Content:  R&B singer Tweet sampled the Gaye/Terrell original for the intro of her 2005 single "Turn Da Lights Off", featuring Missy Elliott. In 2013, American house music producer Chris Malinchak sampled the song on "So Good to Me".
Title: The Essential Luther Vandross
Content: Disc 1 ; 1) "Love It, Love It" ; 2) "Searching" (with Change) ; 3) "The Glow Of Love" (with Change) ; 4) "Never Too Much" ; 5) "A House Is Not A Home" ; 6) "Don't You Know That?" ; 7) "If This World Were Mine" (duet with Cheryl Lynn) ; 8) "Bad Boy / Having A Party" (Single Version) ; 9) "How Many Times Can We Say Goodbye" (duet with Dionne Warwick) ; 10) "Superstar" ; 11) "It's Over Now" (Single Version) ; 12) "Wait For Love" (Single Version) ; 13) "If Only For One Night" ; 14) "Creepin'" ; 15) Anyone Who Had A Heart" ; 16) "Give Me The Reason" ; 17) "There's Nothing Better Than Love" (duet with Gregory Hines) ; 18) "So Amazing" Disc 1 ; 1) "Stop To Love" ; 2) "Bridge 
Title: Her World or Mine
Content:  "Her World or Mine" was written by Brett Beavers, Travis Denning, and Jamie Paulin. Described as a poignant ballad, the song "examines the different trajectories of lives post-breakup." Michael Ray was going through a breakup when he came across the song for the first time and said the timing was perfect: "This would be a very different situation if the song found me two years ago. I believe a song always finds you at the right time. I can sing every word of that song with feeling."

Question: who sang if this world were mine with luther vandross?
Answer: Tammi Terrell.
Cheryl Lynn.