The Epsom Investec Derby on June 6 will take place 30 minutes later than last year in a bid by Channel 4 to increase television ratings.
The Investec Oaks, held the day before on the Friday, will also take place at the new time of 4:30pm. The move comes after last year's event recorded the lowest viewing figures this century.
Channel 4 Racing won the rights to broadcast one of the showpiece events in the racing calendar in 2013 but since then viewing figures have dropped in consecutive years. 1.5 million saw Australia win the 2014 Derby for trainer Aidan O'Brien in comparison to 3.3 million for the BBC's last broadcast back in 2012.
The move also involves pushing the time of the first race back to 2pm.
"We welcome the later start times for the Investec Oaks and Investec Derby, which will enable these blue riband events to be accessible to the widest afternoon audience possible," said Ed Havard, Channel 4's head of TV events and sport, who was speaking to the Racing Post.
Bigger attendance expected
Jockey Club Racecourses, who are Epsom's owners, say the move will increase the overall experience for racegoers.
Their London regional director Rupert Trevelyan said: "We have consulted all stakeholders in this process and consider this change will enhance our customers' experience of the [Derby] festival and the greatest Flat race in the world.
"We believe that from an attendance perspective, in particular for our sponsor and hospitality guests, this adjustment to our timings will enhance the overall enjoyment of their day.
Faugheen heading for Cheltenham
Meanwhile in other racing news, Faugheen will head straight to the Cheltenham Festival according to trainer Willie Mullins.
Unbeaten in eight starts, Faugheen is favourite for the Stan James Champion Hurdle, the feature race on the opening day of the four-day festival. Mullins had previously raised the possibility of entering the seven-year-old for the Red Mills Trial Hurdle at Gowran Park on Saturday but he did not figure amongst the entries.
Speaking to the Racing Post, Mullins said: "Faugheen is fine but we discussed things over the past few days and we've decided that he doesn't need another race before Cheltenham."