Organisers of the Grand National at Aintree have announced a shock change of time for Saturday's race due to the Royal wedding.
The big race is now due to start 25 minutes later at 1610 BST, rather than 1545 as originally planned, and will be televised on BBC One.
Aintree managing director Charles Barnett said: "We have made this decision in consultation with the BBC."
The first four races from Aintree on Saturday will be screened on BBC Two.
It was announced earlier that the Royal wedding will take place at 1230 BST.
Prince Charles and Camilla Parker Bowles will marry at Windsor Guildhall, before a prayer and dedication service is held inside the castle at 1430.
The wedding was postponed because of the Pope's funeral, at which Charles is due to represent the Queen.
BBC One will switch to Aintree from the Royal wedding at 1530 to capture the build-up to the famous race, which has an estimated global audience of 500 million.
Barnett added: "We have taken this decision after a great deal of thought and discussion. We hope it will be a great day for everyone."
He said the wedding should not detract from the race, which sees a field of 40 runners compete over the unique four-and-a-half mile course.
"We wanted to offer British television viewers the best possible chance of an afternoon's entertainment," Barnett told BBC News 24.
A BBC spokesman said: "We are very pleased that members of the public will be able to enjoy both events to the full."
Bookmakers are relishing the delay, estimating the extra time for punters to have a flutter could generate an additional £2.5m in wagers.
SATURDAY TV (All times BST)
BBC One: Royal Wedding
BBC One: Grand National/Final Score 1530 - 1705
BBC Two: Racing from Aintree 1305-1530
The Grand National, being sponsored for the first time this year by John Smith's, attracted a domestic TV audience of 10.3 million viewers in 2004.
It will now be run as the fifth race on Saturday's seven-race programme.
The start time of the National was last affected in 1997 when a bomb scare caused the race to be postponed for two days until 1700 on Monday.
Saturday's National, the the 158th running of the steeplechase, will be preceded by a minute's silence in honour of the late Pope.