The Duke and Duchess Of Cambridge celebrated their second wedding anniversary on Monday, marking two years since what was reportedly Britain’s most expensive wedding in history.

The extravagant affair, which reportedly boasted a guest list of 1,900, cost close to $34 million, according to the Inquisitr. The couple's biggest wedding expense was security, which alone cost approximately $32 million, but was paid for by the crown. The Duchess of Cambridge’s couture wedding gown, on the other hand, designed by Sarah Burton of Alexander McQueen, must have been a heavy blow to the Middleton’s bank account, at a staggering $434,000.

According to Us Weekly, the soon-to-be parents didn’t release any information about how they would spend the milestone. "I'm afraid we're not giving any details on their anniversary plans, as [they are] private,” a spokesman for St. James’s Palace said. But a source close to the couple told the magazine that William and Kate had celebrated their anniversary earlier than usual because the Prince was scheduled to be away fulfilling Royal Air Force obligations on the date of their actual anniversary.

"Today is, by tradition, their paper anniversary," a source told the magazine, referring to the British tradition of giving cotton gifts on a first anniversary, and paper on the second. "And yes, they have bought each other appropriate gifts."

An additional source revealed that the expectant parents had gone out to a special dinner in London last Friday, after taking a tour of Warner Bros. Studios, where they saw the Harry Potter and Batman exhibits. The tour’s instructor, Scott Herron, said of the couple’s magical aptitude that, “they were great. They picked it up really quickly. … I was very impressed.”

Although Prince Harry joined them on their tour, he left separately, with Kate and William making an exit in a Jaguar XJ. The source said that the couple spent the rest of their weekend in Norfolk, before William left for a work stint in Wales.