Charl Brown has been tapped to play Smokey Robinson in the upcoming Broadway musical “Motown,” joining stars Brandon Victor Dixon (as Berry Gordy) and Valisia Le Kae (as Diana Ross).Saycon Sengbloh (“Fela!”), Morgan James (“Godspell”) and Marva Hicks (“Caroline, or Change”) also are among the actors joining the ensemble of some 40 thesps in the show, which chronicles the founding of the titular record label and incorporates the songs of signature artists Ross, Robinson, Stevie Wonder, Michael Jackson and Marvin Gaye, among others. While most in the cast have plenty of stage credits on Broadway and beyond, none are well known enough to attract much consumer notice at the box office (although Gotham legiters will recognize Dixon from stints in “The Color Purple” and the original Off Broadway bow of “The Scottsboro Boys”). Instead producers are banking on drawing crowds with the title and the show’s internationally recognized tunes. Broadway regular Kevin McCollum (“Rent,” “Avenue Q”), Sony Music exec Doug Morris and Gordy produce the tuner, penned by Gordy and helmed by Charles Randolph Wright. Show begins previews March 11 prior to an April 14 opening at the Lunt-Fontanne Theater, where current occupant “A Christmas Story” will wrap up its run after the holidays.