Startling the guards at California’s Hearst Castle last weekend, Jim Belushi impulsively jumped fully clothed into the indoor Roman Pool. He was vis iting San Simeon to raise money for the castle’s Preservation Foundation. Other guests hosted by William Randolph Hearst’s granddaughter, Anne, and hus band Jay McInerney included Belushi’s wife, Jenny, Brooke Shields, Dan Aykroyd with wife Donna Dixon, Sharon Bush, Bettina Zilkha, Wilbur Ross with wife Hilary Geary, Candace Bushnell, CNN’s Robert Zimmerman and Wasserstein CEO Ellis Jones. At the barbecue the next day, Aykroyd and Belushi per formed an impromptu “Rawhide” with Shields playing tambourine.