In just 17 days, the Diamond monarch will officially open the Games during a spectacular ceremony at the Olympic Park.
And as excitement mounts, she joined her husband to greet torchbearers on Day 53 of the torch's UK relay.
In the castle's quadrangle the royal couple watched as 74-year-old Gina Macgregor ran into the open space proudly carrying the flame.
Moments earlier, grey skies which had been threatening all day unleased a torrential downpour. So Mrs Macgregor arrived soaking wet when she was met by the Queen, wearing a rain cape and carrying an umbrella.
Laughing, she told the couple: "I looked fine this morning," to their great amusement.
Joined by London 2012 chariman Sebastian Coe, they then watched the 'kiss moment' as Mrs Macgregor exchanged the flame with Philip Wells, the next torchbearer.
Day 53 of the flame's journey began at the Iffley Road track in Oxford, where legendary middle distance runner Sir Roger Bannister broke the four-minute mile barrier in May 1854.
The 83-year-old was joined by Lord Coe at the track, now renamed after him, and afterwards spoke of the "honour" he felt at being on a list of torch carriers that has "included injured soldiers back from Afghanistan."
Later in the day, as the flame travelled from Oxford to Henley, Olympian Steve Redgrave took a rowing boat to transport it along the Thames.
With an oar in his right hand and the torch in his left, the five-time Olympic rowing gold medalist was cheered on by thousands of spectators lining the route as he helped the flame on its journey.