The singer will join an ever-increasing bill of artists for the show, which will take place at Cardiff's Millennium Stadium on October 8.
Ne-Yo will perform alongside previously-confirmed acts including Christina Aguilera, Leona Lewis, Cee Lo Green, Alexandra Burke and JLS.
The Michael Jackson show will feature a "spectacular production plan and set" and is being touted as a "huge celebration of [Jackson's] legendary music and iconic dance style".
The gig will be broadcast around the world in both 2D and 3D and will be attended by Jackson's family members and friends.
Tickets for 'Michael Forever' are on sale now with prices starting at £55.
Jackson's brothers Jermaine and Randy have criticised the concert for its timing, as it coincides with the manslaughter trial of the late singer's doctor Conrad Murray.
> Michael Jackson fans urge tribute concert cancellation
Watch the music video for Michael Jackson's hit 'Beat It' below: