The Queen's Vase could prove an emotional race at Royal Ascot later today if Disclaimer wins.
Following the death of Sir Henry Cecil last week, this year's renewal is being run in memory of the man who trained more Royal Ascot winners than anybody else, with his record standing at 75.
Disclaimer is trained by Sir Henry's widow Lady Cecil who has taken out a temporary licence to keep the stable running.
The Queen's horse Estimate has won the Gold Cup at Royal Ascot.
The Queen has arrived at Royal Ascot ahead of the Gold Cup which is due to take place at 3.45 pm today.
The Queen will be hoping her horse Estimate repeats its achievement from twelve months ago and triumphs in the race.
Having been tipped to wear pink to the annual event, the Queen instead chose a purple hat.
Racegoers have flocked to Royal Ascot as Ladies' Day kicked off with the usual array of flamboyant hats and dresses.
The annual event is renowned for its display of the latest hat trends and this year's guests did not disappoint.
Racegoers' extravagance does not stop at hats with over over 51,500 bottles of Champagne, 35,000 spears of Asparagus and 2,050 kg of fresh lobster consumed last year.
Racegoers are preparing for Gold Cup Day, also known as Ladies' Day, one of the highlights at Royal Ascot.
Ladies' Day is known for its display of flamboyant and exotic hats and the most extravagant creations.
Racegoers also traditionally bet on the colour of the hat the Queen will wear on the day.
Bookmakers Coral believe she will wear a blue hat and makes the colour its 3-1 favourite.
However, punters have been backing purple and its odds have fallen from 8-1 to 5-1.
The Queen will be hoping her horse Estimate triumphs in Royal Ascot's Gold Cup today as the famous race stages its Ladies' Day.
Over the years the Queen has had 21 winners at the Royal Ascot. This year her filly is a favourite to win.
Gary Lineker, Katherine Jenkins and Aishwarya Rai Bachchan were among the famous faces who visited Royal Ascot today.
The famous five day meeting at the Berkshire racecourse is known for its array of celebrity visitors as well as its racing.
Welsh classical singer Katherine Jenkins said she was attracted to the glamour of the event: "I love Royal Ascot, it's just so old-fashioned - old-fashioned glamour, old-fashioned traditions."