Bob Hope underwent emergency surgery on Thursday to stop some gastrointestinal bleeding. The legendary entertainer, who turned 97 on May 29, is in critical but stable condition at a hospital near his Palm Springs, Calif., home. He is expected to recover fully, his family says. "Both Mrs. Hope and daughter Linda are very optimistic and ask that everyone simply keep Bob in their prayers," said a hospital spokeswoman. On May 9, the Smithsonian in Washington unveiled the new Bob Hope Gallery, filled with his memorabilia. He did not appear at the ceremony, though he was resting at a nearby hotel. His last public appearance was in November 1999, when he and wife Dolores flicked the switch to turn on the Christmas lights at Disneyland. "He's a very strong guy," Dolores Hope assures the PEOPLE.com Daily.