Guests who managed to receive an invite from Her Majesty were treated to an exclusive sit-down dinner and private tour of the castle, hosted by the Queen herself.
Actress Helena Bonham Carter was one of the A-list celebrities whose presence was requested by the Queen and her royal consort.
Speaking to the Radio Times, the 53-year-old star claimed that she attended the affair about a decade ago, along with fellow actors Daniel Craig and Rachel Weisz.
“It’s fun! Rachel Weisz was there with James Bond,” Helena said.
“We had supper and the Queen and Prince Philip gave us a tour.”
She also revealed that when it came time to retire for the evening at the royal residence, she was given one of Prince Charles' rooms to sleep in.
The Crown actress went on to say that as a special treat, all of the guests got to explore or experience something historical from the Queen’s archive.
“I had a letter from Lionel Logue, who was the King’s speech therapist. It was really touching,” she said.