“Robin Roberts Presents: Mahalia” star Rob Demery revealed the emotional moments as he got in character for his role as Martin Luther King Jr. on Lifetime’s upcoming biopic of “Queen of Gospel” Mahalia Jackson. The film, which stars “Orange is the New Black” star Danielle Brooks in the title role, is a retelling of some of the icon’s behind-the-scenes moments as an activist and dear friend of Martin Luther King Jr.