The Vatican announced the pope's funeral would take place Friday, the same day Charles and Camilla had been scheduled to wed.
The prince, however, will attend the funeral in Rome. The wedding was postponed until Saturday.
Charles and Camilla will wed in a civil ceremony at Windsor's Guildhall and then receive a blessing from Archbishop of Canterbury Rowan Williams at Windsor Castle.
Sarah Ferguson has not been invited to the prince's wedding because of a six-year rift, the Mirror reported Monday.
The pair parted on bad terms after a dinner at Highgrove, the prince's home, in 1999.
Her two children, Beatrice and Eugenie, and former husband, Prince Andrew, will attend.