Prince Charles and Camilla Parker Bowles will marry at 1230 BST on Saturday, Clarence House has announced.
The couple had planned to wed on Friday in Windsor
The Royal wedding, which had been set for Friday, will take place at Windsor Guildhall, followed by a dedication service inside the castle at 1430 BST.
This will be followed by a reception, which the couple intend to leave at around 1800 BST, said a spokeswoman.
The wedding was postponed because of the Pope's funeral, at which the prince is due to represent the Queen.
Events will also affect the Grand National at Aintree, with a change in start time from 1545 BST to 1610 BST.
Following the decision to change the wedding date, Downing Street confirmed Tony Blair would also attend.
The church blessing, in St George's Chapel at Windsor Castle, will be conducted by the Archbishop of Canterbury, and will be attended by the Queen.
Three other weddings booked for the Guildhall on Saturday will not be disrupted.
Grace Beesley, 33, from Windsor, who is marrying Fraser Moores, 34, in the Guildhall at 1400 BST on Saturday, said she was "very excited" by the prospect of sharing her wedding day with Charles and Camilla.
The couple are scheduled to be the first married in the hall after the royal couple.
'Excited and terrified'
Miss Beesley said: "We won't have to make any changes to our wedding - the registrar rang us this morning and told us that - so it will just be another dimension to the day and a bit more exciting."
Mr Moores said he expected Windsor to be busier as a result of the postponement, but added: "I don't care - bombs could fall from the sky and I'm looking forward to still getting married."
Following on at 1500 BST are entrepreneur Deborah Biltcliffe, 34 and Army major Tom Crapper, 34, who live in Bath.
Miss Biltcliffe said they both thought it was "exciting" that the weddings now coincided but said there was little to compare between the events, other than that both couples loved each other.
"We're clearly focused on why we're there and getting married to each other and our own party so I don't think it will change our day at all," she said.
An hour later 31-year-old accountant Nadine Hopkins will marry carpenter Jim Hooper, 30, at the Guildhall.
Miss Hopkins said she was "excited and terrified" about the presence of the world's media.
A spokeswoman for Clarence House said: "Largely the arrangements will be the same.
"However, one of our main priorities is not to disrupt the civil ceremonies which will be taking place on that day. Further details about the timing will be released as soon as possible."
Charles's quest to marry Camilla has been dogged by setbacks since their engagement was announced in February.
They have included the Queen's decision to stay away from the civil ceremony, the row over whether Mrs Parker Bowles would ever be known as Queen and the change in venues from Windsor Castle to the local town hall.