Prince William paid a “touching” tribute to his cancer-stricken wife Princess Kate during a key royal event this week, according to Richard Fitzwilliams. The Prince of Wales was among a cohort of royals to welcome Emperor Naruhito and Empress Masako of Japan on Tuesday. The ceremony saw the Emperor, Empress, King Charles, Queen Camilla and Prince William all standing on a stage at Horse Guard’s Parade. According to Fitzwilliams, William made a touching subtle gesture to his absent wife. “William has played an important role”, he said. “When there was the meeting on the Horse Guard’s Parade, th…