Which artist who contributed to R Kelly's "Double Up" album began his solo career in 2000 ?
Double Up (R. Kelly album):  The album features the contributions with guest appearances and also the productions, which was handled by R. Kelly, alongside with Swizz Beatz, The Runners, Snoop Dogg, Khao, Nelly, Chamillionaire and Polow da Don. Nelly:  Under Universal, Nelly began his solo career in the year 2000, with his debut album "Country Grammar", of which the title-track was a top ten hit.
Nelly