Princess Kate set to miss key royal fixture tonight as King Charles hosts glitzy event

will miss the Royal Family's most glamorous event of the year, which will be held at tonight - complete with a white tie and tiaras dress code.

King Charles is hosting the annual white-tie Diplomatic Corps reception on November 19, which sees the royals host 500 diplomats and their spouses, who all come dressed up in their fanciest attire.

The King is set to be joined by other members of the Firm including and Prince William, but the Princess of Wales is not expected to be in attendance.

Kate, 42, in September after the conclusion of her cancer treatment.

The Princess underwent major abdominal surgery in January, after which doctors discovered cancer had been present, and she undertook a course of preventative chemotherapy.

Tonight's reception is , where guests are invited to the State Rooms at the Palace.

The event is normally held on the first Tuesday in December but has been brought forward as it would have clashed with a State Visit of the Amir of Qatar this year.

In attendance will be all ambassadors and High Commissioners at the foreign missions in London, , and other leading public figures.

Over 1,500 guests are expected to attend from around 130 different countries, making it the biggest reception held at the Palace all year.

The dress code is national dress, white tie or court dress, which involves knee breeches for male members of the British Royal Family. Women wear a national dress or a long evening dress, as well as tiaras for the royals.

After members of the Royal Family greet guests, a drinks reception follows, then a buffet dinner is held, followed by dancing in the Ballroom.

Last week, , and it was the first time this year she had made two appearances on two consecutive days following her cancer diagnosis and subsequent chemotherapy treatment.

Looking ahead to next month, at Westminster Abbey. Supported by The Royal Foundation, the Princess of Wales will host her fourth 'Together at Christmas' Carol Service.

The service will shine a light on individuals from all over the UK who have shown love, kindness and empathy in others in their communities, whether on a personal level with friends and family, through their work or as they selflessly give up their time through volunteering, as stated on the Royal Foundation .

There are set to be 1,600 people in attendance at Westminster Abbey for this year's Christmas event.