Kevin Smith has some major star power in his upcoming Netflix series “Masters of the Universe: Revelation.” “Star Wars” veteran Mark Hamill and “Game Of Thrones” star Lena Headey will star in the show, along with “Buffy” herself Sarah Michelle Gellar. Hamill, also known for voicing the Joker, will play Skeletor, Headey will voice Evil-Lyn, and Gellar will play Teela.