Robin Williams is set to undergo surgery for an aortic valve replacement after being admitted to a south Florida hospital earlier this week, it was announced on Thursday. Williams, 57, has canceled all performances of his one-man show, Weapons of Self-Destruction, which was on a 80-city tour when he suffered a shortness of breath. "I'm so touched by everyone's support and well wishes," the Oscar-winning actor said in a statement. "This tour has been amazing fun and I can't wait to get back out on the road after a little tune-up." The tour set resume in the late spring. (Photo: WENN)