King Charles III, Camilla, the queen consort, Prince William and Kate Middleton all dressed in their royal best Tuesday night as they hosted a formal white tie dinner at Buckingham Palace. 

The annual Diplomatic Reception comes after William and Kate returned from their first trip to the U.S. in eight years and as Prince Harry and Meghan Markle prepare to receive the Robert F. Kennedy Human Rights Ripple of Hope Award at a New York gala Tuesday. 

Camilla and Kate both glimmered in the Belgian Sapphire and Lotus Flower tiaras respectively as they greeted guests for the event. 

The Belgian Sapphire tiara, also known as the Victorian Sapphire tiara belonged to Queen Elizabeth II who died at the age of 96 in September. 

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Kate Middleton talking to guests

Kate Middleton wore the Lotus Flower tiara for the first time since 2015 on Tuesday.  (Victoria Jones - Pool/Getty Images)

The Princess of Wales looked svelte in a red patterned Jenny Packham gown and a pair of diamond earrings that had belonged to the queen. 

Kate Middleton smiling

Kate Middleton wore a Jenny Packham gown.  (Victoria Jones - Pool/Getty Images)

The queen consort wore a black Anne Valentine gown along with a diamond and sapphire necklace that matched her tiara that was a wedding gift to the queen from her father, King George VI. 

Prince WIlliam and Kate Middleton arrive at the reception

Prince WIlliam and Kate Middleton co-hosted the event with King Charles III and Camilla, the queen consort, after their trip to Boston. (Max Mumby/Indigo/Getty Images)

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The Lotus Flower tiara, which Kate last wore in 2015, was fashioned by the Queen Mother out of a necklace her husband George VI gave her for the wedding in 1923.

King Charles shaking hands

Queen Elizabeth II was supposed to host the Diplomatic Reception in March, but it was postponed by Russia’s invasion of Ukraine. (Victoria Jones - Pool/Getty Images)

The event, which was held for the first time since before the pandemic, was reportedly supposed to be hosted by the queen last March at Windsor Castle, but was postponed by Russia’s invasion of Ukraine.

Camilla smiling

Camilla, the queen consort, wore the Belgian Sapphire tiara that was owned by Queen Elizabeth II.  (Victoria Jones - Pool/Getty Images)

The reception "celebrates the presence in London of one of the largest Diplomatic Corps in the world," according to Buckingham Palace. 

King Charles shaking hands with a guest.

King Charles II greeted guests during the Diplomatic Reception Tuesday.  (Victoria Jones - Pool/Getty Images)

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King Charles and Camilla arrive at reception

King Charles III and Camilla, the queen consort arrive at the Tuesday reception. (Max Mumby/Indigo/Getty Images)

Meanwhile, on Tuesday Harry and Markle attended the 2022 Ripple of Hope Award Gala, emceed by Alec Baldwin, on Tuesday night in New York City as reports swirl over their upcoming "Harry & Meghan" docuseries release.

Meghan Markle and Prince Harry

Meghan Markle and Prince Harry arrive to the 2022 Ripple Award Gala in New York on Tuesday night. (Getty Images)

The Sussexes were picked to receive the award from the Robert F. Kennedy foundation in "recognition of their work on racial justice, mental health, and other social impact initiatives through their Archewell Foundation," a press release from the human rights organization said.

Earlier this week, Netflix released a trailer for Harry and Meghan’s tell-all documentary in which Harry talks about the "pain and suffering of women marrying into" the royal family, calling the relationship with the palace and the tabloids a "dirty game." The first part of the documentary will air on Thursday.