Prince William, Prince of Wales and Catherine, Princess of Wales attend a service to commemorate the life of Her Late Majesty Queen Elizabeth II at St Davids Cathedral on September 8, 2023 in St Davids, Wales.

Aside from the King and Queen, Princess Anne took part in the event inher role as Gold Stick in Waiting.

However, the Prince and Princess of Wales didn’t attend the historic event.

King Charles and Queen Camilla at the State Opening of Parliament on Nov. 7, 2023.LEON NEAL/POOL/AFP via Getty Images

King Charles III, wearing the Imperial State Crown and the Robe of State, sits beside Britain’s Queen Camilla, wearing the George IV State Diadem, as he reads the King’s speech from The Sovereign’s Throne in the House of Lords chamber

LEON NEAL/POOL/AFP via Getty Images

It’s not required for the heir to the throne to attend the State Opening of Parliament, but King Charles accompanied his mother,Queen Elizabeth, several times throughout her reign. He attended for the first time in 1970.

But Prince William had a significant event of his own on Tuesday:the Earthshot Prize awards ceremonyin Singapore. The Prince of Wales, 41, hit the green carpet alongsideCate Blanchett,Hannah WaddinghamandSterling K. Brownas they honored thenext wave of environmentalistscoming up with answers to the planet’s most pressing problems.

Although Princess Kate, 41, joined her husband at theinaugural awards ceremonyfor the environmental prize in London in October 2021 and for thesecond cyclein Boston in December 2022, she did not make the trip to Singapore. She stayed in the U.K. to support their sonPrince Georgeas hetackles school exams.

“Catherine is very sorry she can’t be here,”Prince William said in Singaporethis week. “She is helping George through his first set of major exams.”

Cate Blanchett and Prince William at the Earthshot Prize awards on Nov. 7, 2023.Chris Jackson/Getty

Prince William Cate Blanchett Earthshot Awards Ceremony Singapore 11 07 23

Chris Jackson/Getty

In May 2022, Prince William was present at the State Opening of Parliament for the first time. Buckingham Palace announced that the Queen, who died in September 2022 at age 96, wouldmiss the event due to “episodic mobility problems.“For the first time,Charles represented his motherand read the Queen’s Speech.

Queen Elizabeth delegated her royal duty of opening a new session of Parliament to her son and grandson via a letter patent, which enabled them to jointly exercise that function. Both were acting as Counsellors of State, and two Counsellors of State are required to perform any of the monarch’s constitutional duties.

Princess Kate has not yet attended the State Opening of Parliament.

Can’t get enough ofPEOPLE’s Royals coverage?Sign up for our free Royals newsletterto get the latest updates on Kate Middleton, Meghan Markle and more!

Royals at the Scotland coronation celebrations on July 5, 2023.Jane Barlow - Pool/Getty Images

King Charles III, the Prince of Wales, known as the Duke of Rothesay while in Scotland, Queen Camilla and Princess of Wales. known as the Duchess of Rothesay while in Scotland attend the National Service of Thanksgiving and Dedication for King Charles III and Queen Camilla, and the presentation of the Honours of Scotland, at St Giles' Cathedral

Jane Barlow - Pool/Getty Images

“Charles is leading the way for them already, and [William and Kate] are both involved in decision-making behind the scenes. They are ready and willing to do the job — and Kate is very much a part of that,” a friend of the princesspreviously told PEOPLE.

source: people.com