Browse through our gallery to feast your eyes on all of the night's best photos!
Pictured here: Frederik walked into his milestone in full military regalia, flaunting impressive medals and a sword. He was flanked by his ever exquisite wife Crown Princess Mary and his monarch mom, Margrethe II, both of whom looked stunning. The powerful trio turned heads in their formal ensembles as they entered the hall.Photo: © Getty Images
Once everyone was settled inside The Knights Hall, Queen Margrethe gave a lovely birthday speech for her son before the crowd of royals and dignitaries.
Photo: © Getty Images
Frederik and Mary looked very much in love as they celebrated the Prince's big 5-0.
Photo: © Keld Navntoft, Kongehuset
Attendees like Crown Princess Victoria and Prince Daniel were shown to formal tables, standing until the evening's guests of honour were seated.
Photo: © Getty Images
Can I have this dance? The birthday boy and his wife opened up the dance floor, happily taking a spin across the sprawling palace.
Photo: © Keld Navntoft, Kongehuset
Queen Margrethe's sister Princess Benedikte made a splash in a baby blue gown. She also wore an intricate tiara.
Photo: © Getty Images
Crown Princess Victoria and Prince Daniel made the trip from Sweden to celebrate Frederik. A pretty pair, Victoria looked especially delightful in a floral gown and shiny crown.
Photo: © Getty Images
Victoria's parents King Carl Gustaf and Queen Silvia were also in attendance, looking as regal as ever.
Photo: © Getty Images
King Willem-Alexander and Queen Maxima of the Netherlands followed their glamorous state visit to Luxembourg with a stop at the glitzy party.
Photo: © Getty Images
Belgium's King Philippe and Queen Mathilde were on hand for the festivities, where she looked spectacular in a red one-shoulder gown with matching lips and accessories and, of course, a dazzling tiara.
Photo: © Getty Images
Countess Alexandra, the former wife of Prince Joachim, opted for a very faint pink lace floor length gown, which she paired beautifully with dangling diamond earrings and a tiara.
Photo: © Getty Images
Crown Prince Haakon and Crown Princess Mette-Marit of Norway were also seen waltzing into the palace.
Photo: © Getty Images
Talk about an entrance! The Crown Prince and Crown Princess took a carriage ride that seemed straight out of a fairy tale to get to the palace gala. Royal fans gathered to send their well wishers, and even excitedly peeked out their window to watch.
Photo: © Getty Images
The sweet couple waved to their supporters as they rode to the palace from the Royal Stable.
Photo: © Keld Navntoft, Kongehuset