That's when Kate Middleton and Prince William, surrounded by their immediate families, are officially scheduled on the balcony of Buckingham Palace and expected to kiss – just as the groom's parents, Prince Charles and Princess Diana, did 30 years ago.
They will then watch the spectacle of a Royal Air Force flyover, the palace confirmed Friday.
As for the official, to-the-minute "ceremonial timings" on the big day (all London time):
Between 8:15 a.m. and 9:45 a.m.
The general congregation will arrive at the Great North Door of Westminster Abbey.
From 9:50 a.m.
Governors-General and Prime Ministers of Realm Countries, the Diplomatic Corps and other distinguished guests arrive at the Abbey.
The Bridegroom and Prince Henry of Wales leave Clarence House. They arrive Westminster Abbey at 10:15 a.m.
Members of Foreign Royal Families arrive at Westminster Abbey from Buckingham Palace.
Mrs. Michael (Carole) Middleton and Mr. James Middleton leave the Goring Hotel. They arrive Westminster Abbey at 10:27 a.m.
Members of the Royal Family (except those listed below) leave Buckingham Palace. They arrive Westminster Abbey at 10:30 a.m.
The following Members of the Royal Family leave Buckingham Palace. They arrive Westminster Abbey at 10:40 a.m.:
The Duke of York
Princess Beatrice of York
Princess Eugenie or York
The Earl and Countess of Wessex
The Princess Royal and Vice Admiral Timothy Laurence
The Prince of Wales and The Duchess of Cornwall leave Clarence House. They arrive Westminster Abbey at 10:42 a.m.
The Queen and The Duke of Edinburgh leave Buckingham Palace. They arrive Westminster Abbey at 10:45 a.m.
10:48 a.m.The Bridesmaids and Pages leave the Goring Hotel. They arrive Westminster Abbey at 10:55 a.m.
The Bride, accompanied by Mr. Michael Middleton, leaves the Goring Hotel for Westminster Abbey.
The Marriage Service begins (and will be relayed by audio speakers along the route).
The Carriage Procession of the Bride and Bridegroom with a Captain's Escort of the Household Cavalry, followed by The Queen's Procession with a Sovereign's Escort of the Household Cavalry, leaves Westminster Abbey for Buckingham Palace.
The Bride's Carriage Procession arrives at Buckingham Palace.
Members of the Royal Family and Members of Foreign Royal Families arrive at Buckingham Palace.
From 12:40 p.m.
Other guests for the Reception arrive at Buckingham Palace.
The Queen and the Bride and Bridegroom, together with their Families, appear on the Balcony.
Fly Past by the Royal Air Force and Battle of Britain Memorial Flight.
Then the Queen's reception begins!
Reginald Davis / REX Features