British actor Ian McKellen, best known as Gandalf in the “The Lord of the Rings” movies and Magneto in the “X-Men” franchise, will be the subject of a feature documentary, “McKellen: Playing the Part.” The pic, directed by Joe Stephenson, is based around an exclusive 14-hour interview with McKellen. The documentary will feature rare archive material of early work from stage and screen, never-before-seen photography from McKellen’s private collection, and cinematically reconstructed scenes from his life. McKellen has been Oscar nominated twice: for “Gods and Monsters” in 1999 and “The Lord of the Rings: The Fellowship of the Ring” in 2002. He has been Emmy nominated five times.