Frankie Dettori will ride the favourite Golden Horn as he bids to win the 236th running of the Derby at Epsom.
A crowd of more than 100,000 is expected at the Surrey track for flat racing's premier Classic race.
Dettori, 44, returned from a six-month drugs ban at the meeting two years ago but this will be his first ride in the big race since 2011.
Rivals in a 12-strong field for the mile-and-a-half contest include Jack Hobbs, Giovanni Canaletto and Elm Park.
What's the weather/going?
Epsom was bathed in sunshine on Friday for Ladies' Day and more of the same is expected for Derby Day.
Temperatures are likely to top 20C, with the going officially described as Good to Firm.
Clerk of the course Andrew Cooper said: "The risk of thunderstorms has passed and it should be a dry day, and feel fresher."
That is good news for punters on the open-top double-decker buses which traditionally line the rail of the racecourse.
Who's lining up?
Number, horse, breeding (UK unless stated), trainer, jockey, odds
1 CARBON DATING (IRE) Pat Shanahan IRE Ronan Whelan 200-1
2 ELM PARK Andrew Balding Andrea Atzeni 8-1
3 EPICURIUS Criquette Head-Maarek FR Thierry Thulliez 18-1
4 GIOVANNI CANALETTO Aidan O'Brien IRE Ryan Moore 9-1
5 GOLDEN HORN John Gosden Frankie Dettori 7-4
6 HANS HOLBEIN Aidan O'Brien IRE Seamie Heffernan 16-1
7 JACK HOBBS John Gosden William Buick 5-1
8 KILIMANJARO Aidan O'Brien IRE Joseph O'Brien 20-1
9 MOHEET Richard Hannon Pat Dobbs 40-1
10 ROGUE RUNNER (GER) Andreas Wohler GER Oisin Murphy 100-1
11 STORM THE STARS (USA) William Haggas Pat Cosgrave 20-1
12 SUCCESS DAYS Ken Condon Shane Foley 16-1
|Racing correspondent Cornelius Lysaght's verdict:|
|1. Jack Hobbs, 2. Hans Holbein, 3. Storm The Stars.There are doubts about the stamina of Golden Horn, about ground conditions for Elm Park and Success Days and about being beaten and looking awkward just 13 days ago for Giovanni Canaletto.Jack Hobbs is sure to stay and the going should be fine; Hans Holbein really caught the eye with his wide-margin Chester success when Storm the Stars was third before subsequently winning in decent style.|
The Dettori story
Dettori will look to complete the latest chapter in a rollercoaster career by winning the Derby for a second time. He triumphed at the 15th attempt on Authorized in 2007.
The Italian-born rider made headlines around the world in 1996 when he rode his 'Magnificent Seven' at Ascot - all the winners at one meeting at combined odds of more than 25,000-1.
Four years later he survived a light aircraft crash in which the pilot died, and has gone on to triumph in more than 200 Group One races at the highest level.
He enjoyed a highly successful partnership with Sheikh Mohammed's Godolphin racing team for 18 years but he left in 2013 and was later given a six-month ban after testing positive for cocaine.
What's it like at the Derby?
Derby Day is a unique British sporting occasion, with crowds packing the infield of the course, where there are bookmakers, funfair rides, a large contingent of travellers and even a Big Top.
The course itself is like a rollercoaster ride - the runners climbing up a steep incline before they sweep around Tattenham Corner and into the home straight, with undulations throughout the track.
On the other side of the infield are the main stands, including the Queen's Stand where male racegoers are required to wear Morning Dress.
The Queen is once again expected to be in attendance, watching on with her binoculars from the Royal Box, taking in the vista of top hats and tails, swarms of punters and some high-quality thoroughbreds.
All's well that ends well?
Every year the predicted name of the Derby winner appears on a wishing well at the Amato Inn in Epsom.
The pub fields calls from around the world from people who want to know which runner has been chalked on the well, supposedly by a traveller who arrives in the dead of night.
Zawraq was written on the well earlier in the week, but scrubbed off when declared a non-runner on Thursday and replaced by Giovanni Canaletto.
So how successful is this method of finding the winner?
At one stage in recent memory, it was said to have been correct eight times in 12 years, but punters should be warned - it last came up trumps in 2009 with Sea The Stars.