Oprah Winfrey and her “Selma” castmates celebrated Martin Luther King, Jr. Day early on Sunday by marching through Alabama with civil right activists. Hundreds joined Selma producer and star Oprah, director Ava DuVernay and leading men David Oyelowo and Common, among others, as they marked the 1965 protest that provided the backbone for the Oscar-nominated movie. The quartet and activists marched from Selma City Hall to the city’s Edmund Pettus Bridge, where civil rights protesters were beaten by police officers 50 years ago this year.