Additional vocals, later added to Gaye's deluxe edition re-issue of I Want You, showcase two different lead vocal takes by Marvin. Gaye's lead vocals brought in both falsetto and a gospel approach near the ending coda of the song. The instrumentation included strings, then an important ingredient to soul and disco-styled music in the seventies, bongos, bell tree, percussive congas added a jazz feel to the song, the bass guitar notes and guitar riffs bring in a funk ingredient, while additional guitar (provided by Ray Parker Jr., by now a Los Angeles session musician) put in an added rock element. The song was a fusion of different genres, an unusual mix for Gaye. Purportedly recorded at Marvin's Room, the singer's new recording studio in Los Angeles, Marvin also reportedly recorded the song while lying on the back of his sofa according to Ware, who said that he couldn't see Gaye at first but then discovered a laid-back Marvin delivering the song in his trademark tenor vocals. When Ware played Gaye the rough draft of "I Want You", Marvin, then inspired by his relationship with his girlfriend Janis Hunter, was motivated to record a convincing performance of the song, which was about a man trying to convince a wayward lover that he wanted the woman to love him as much as he loved her. Marvin, who called himself a perfectionist, had struggled with creating a follow-up album to Let's Get It On. But after hearing it, he convinced Ware to give some of the songs to Marvin Gaye, who was coming off the release of his acclaimed 1973 record, Let's Get It On, his final duet recording with Diana Ross and a commercially successful live album and was coming off a US tour at the time. When Ware, who was also signed to the label as a solo artist, presented the rough draught of his album to Motown-CEO Berry Gordy, the mogul was appreciative of the songs, including a rough version of "I Want You". Originally conceived by Motown songwriter Leon Ware and his songwriting partner "T-Boy" Ross, it was originally intended to be included in Ware's Musical Massage album.