Following the closing of Detroit’s Hitsville USA studios in 1972, Motown had primarily moved its location to Los Angeles, where Gaye also relocated where he recorded the Trouble Man album. Gaye invited several musicians, including some from the Funk Brothers and musicians from Hamilton Bohannon‘s band.
Gaye would compose five different versions of the title track, including an alternate vocal version, which was used primarily for the film’s intro. The alternate version featured Gaye double-tracking two lead vocal parts into one, bringing his falsetto vocals with his tenor on top of the falsetto. The single version, which was also featured on the soundtrack, would feature a single lead vocal take. The other three versions were put on the album as instrumentals with Gaye providing synthesizer keyboards while saxophone solos (and occasionally guitar) accompany him.
The only other songs in which Gaye vocalized harmonies or performed lead vocals included “Poor Abbey Walsh”, “Cleo’s Apartment”, “Life is a Gamble”, “Don’t Mess with Mister T” and “There Goes Mister T”. (Source: WiKipedia and AllMusic)