Alicia Keys

Jennifer Hudson joining “The Voice” as a coach

“American Idol” alum Jennifer Hudson is heading back to her reality TV singing competition roots.

The Oscar-winner has signed on to serve as a coach for the upcoming season of “The Voice,” stepping in for Alicia Keys, who is focusing on producing a new album.

Hudson will join “Voice” mainstays Adam Levine and Blake Shelton as well as returning coach Miley Cyrus. The “Dreamgirls” star served as a coach for the show’s U.K. edition earlier this year.

“Jennifer…