Based on the life of iconic music mogul Gordy, the show is to open at the Lunt-Fontanne Theatre April 14.
Additional casting will be announced shortly, the musical's producers said Monday.
Dixon earned a Tony Award nomination for his performance in "The Color Purple" on Broadway and received a Drama Desk Award nomination for his work in "The Scottsboro Boys" off-Broadway.
LeKae has appeared in the Broadway musicals "The Book of Mormon," "Ragtime," "110 in the Shade" and "The Threepenny Opera."
Directed by Charles Randolph-Wright, "Motown: The Musical" will feature a book by Gordy, and music and lyrics from Motown's famous song catalog.