Prince William, Kate Middleton enjoy late night party with King Charles

Prince William and Princess Kate were all smiles and in good spirits as they left King Charles birthday bash after enjoying a late night party with the monarch to celebrate his milestone on Tuesday.

The Prince and Princess of Wales were spotted beaming from ear to ear as they appeared together in their luxury car after attending midnight party, looking smashing in their chic outfits with smiles on their faces.

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The 41-year-old Princess put on her true beauty on display as she was sitting next to her husband William in their car, wearing an emerald, sequin-embellished gown.

On the other hand, William, the heir to the throne, looked dapper in a crisp white shirt and black blazer. The couple's romantic mood was suggesting as they were planning something big for the future.

The royal party was also attended attended by Princess Beatrice, Princess Margaret’s daughter Lady Sarah Chatto and, Princess Anne’s daughter Zara Tindall, as well as her husband, former rugby player Mike Tindall.

The party was also surprisingly attend by Queen Camilla's son from her first marriage, Tom Parker-Bowles. However Prince Harry was missing from the big royal event.

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The phone call that melted months-long ice between the father-son duo went so well that Charles and Harry have penciled in yet another over-the-phone catch-up for next week in what could be a “turning point” in their relationship, according to reports.

There are also reports that King Charles received a pre-recorded video of his grandchildren, Prince Archie, four, and Princess Lilibet, two, in which they sing Happy Birthday to the monarch.

Prince Andrew, his ex-wife Sarah Ferguson and their youngest daughter Princess Eugenie, who still shares strong bond with Harry, were not seen celebrating the King's event.