Complex sentence: On February 17th, actor Micah Hauptman was added to the cast of the film in the role of filmmaker and mountaineer David Breashears, who directed the 1998 IMAX documentary film "Everest".
Split into simpler sentences: On February 17th, actor Micah Hauptman was added to the cast of the film. He'll play the role of filmmaker and mountaineer David Breashears, who directed the 1998 IMAX documentary film "Everest".