Roughly 650 guests gathered at Buckingham Place to celebrate Prince William and Catherine Middleton after the couple exchanged vows at Westminster Abbey on Friday.
"It was very cozy," says Alex van Straubenzee, father of the late Henry van Straubenzee, a close friend of William's. "There was a wonderful relaxed atmosphere. There were lots of people there – even in a place as big as Buckingham Palace. I won't say it was informal, but everyone was having a wonderful time."
After guests mingled with the royals, both Prince Charles and Prince William gave touching speeches.
"It was a very happy scene," a male guest told PEOPLE. "We cut the cake, and then Charles gave a lovely speech about his son and spoke about him in a very lovely way."
While guests nibbled on canapés, such as Cornish crab salad and quail eggs, the newlyweds were toasted with Pol Roger NV Brut Reserve champagne. For dessert, partygoers had their choice of two wedding cakes – a traditional fruit cake, as well as a chocolate biscuit cake requested by Prince William that is made from a Royal Family recipe.
"What I found amazing was the ability for the royal family to wander into a room with 600 people and just say thank you [to so many of them]," Dr. Robert Acheson, who was the former head of St. Andrew's School where Kate went to elementary school, told PEOPLE. "To be able to just go in, talk very freely and move on."
Wedding Was a DreamAs for the ceremony itself, guests couldn't say enough good things about the momentous event. From the beautiful setting and music to the crowd reaction and the poised bride and groom, many in attendance were moved by the experience.
Courtesy British Monarchy
The fairy-tale continued as the Duke and Duchess of Cambridge drove away from the palace in an Aston Martin convertible.
But the celebration doesn't stop there. Prince Charles is throwing the newlyweds a dinner dance at the palace this evening.
Reporting by LIZ CORCORAN, SIMON PERRY and CHARLOTTE TRIGGS in London