A new book by royal biographer Robert Jobson has revealed surprising details about the wedding day of Prince William and Princess Kate Middleton.

The marriage of Kate Middleton and Prince William on April 29, 2011, remains one of the most-watched royal weddings in history. While millions around the world tuned in to witness the televised ceremony at Westminster Abbey and the iconic balcony kiss at Buckingham Palace, there were exclusive behind-the-scenes moments that the public never saw.

Despite a staggering 1,900 guests attending the ceremony, the subsequent receptions were far more exclusive. Queen Elizabeth hosted a luncheon for 650 guests, followed by an intimate evening reception organized by Prince Charles (now King Charles) for just 300 guests, both held at Buckingham Palace.

In his new book, Catherine: Princess of Wales, Jobson shares anecdotes from the evening reception, described by one guest as “the most magical party you could imagine.”

Jobson writes that only the couple’s closest friends were invited to this private celebration, accompanied by live music from one of their favorite artists, Ellie Goulding. Goulding serenaded the couple’s first dance with a rendition of Elton John’s Your Song, setting the romantic tone for the night.

After her performance of Your Song, Goulding continued with a lively set, including her hit Starry Eyed and a cover of Mr. Brightside by The Killers—one of William and Kate’s favorite tracks. The newlyweds didn’t just enjoy the music; they sang and danced along to classics like She Loves You by The Beatles before a dazzling fireworks display lit up the sky.

A 2011 guest shared with People: “William and Kate were at the center of it all, dancing with such joy. They stayed until the very end and truly embraced the celebration.”

One particularly unexpected highlight, as revealed by Jobson, was when the opening notes of You’re the One That I Want from Grease played. William and Kate surprised everyone by taking to the dance floor, channeling Danny and Sandy, mouthing the lyrics to each other with beaming smiles. The crowd erupted in excitement at this theatrical and playful moment.

But the surprises didn’t stop there. Guests were led to the palace’s immaculate back lawn, where a quirky spectacle awaited—a convertible Fiat adorned with balloons. “They got into the car and drove along the gravel paths, with fireworks bursting in the sky for two full minutes,” a guest recounted.

The night wrapped up at 3 a.m., marking the end of a royal wedding unlike any other—a perfect blend of tradition, romance, and pure joy.