5. R. (1998)
One of Kelly’s most underrated efforts and highest selling album finds the performer opening up the studio to outside producers. The inclusion of the Trackmasters signals Kells’ two-fisted run as the hip-hop world’s go-to soul man. The likes of Keith Murray, Cam’ron, Nas, Foxy Brown and Jigga injects the streets into the sexy mix. R. contains arguably Kelly’s most barebones, startling testimonies of lost love and regret (“When A Woman’s Fed Up”). Then there’s his noteworthy continued evolution as a legit pop music craftsman. Indeed, “I Believe I Can Fly” was no fluke as evident by his self-penned duet with Canadian diva Celine Dion (“I’m Your Angel”), which no one saw coming.