Katherine Heigl caused quite a stir at a Saturday performance of “The Book of Mormon.” A spy reports the star and her mother arrived at the show 20 minutes after it started, and guests seated in her row had to get up. Ten minutes later, Heigl’s husband, Josh Kelly, showed up, and they had to move again to let him get to his seat next to her. Attendees also said the “Grey’s Anatomy” actress “wore big dark sunglasses and discreetly bent down and puffed on an electronic cigarette during the show.” Heigl’s rep had no comment.