Stars including Demi Moore, Ricky Martin, Cara Delevingne took to Instagram to update fans on the royal festivities at the wedding breakfast, which followed the public ceremony at Windsor Castle.
Celebs gathered at Windsor Castle's St George's Hall, where the 850 guests enjoyed finger food and wedding cake all washed down with Pol Roger champagne.
One guest captured a tender moment between Eugenie and Jack at the reception.
Stella McCartney shared a glam snap of Demi Moore inside the castle.
Robbie Williams and wife Ayda Field posed together in their hotel room ahead of the big day.
Ricky Martin was in fine form, larking around with fellow guests.
Cara Delevingne and her sisters Poppy and Chloe as well as Derek Blasberg and Dave Gardner took some time ahead of the two-day party.
Richard Branson's son, Sam posed with British footballer Jamie Redknapp and comedian Jack Whitehall.