As the head of the Commonwealth, the annual celebration of the 54-country realm is one of the most important days of the royal calendar for Queen Elizabeth. But with increasing discomfort in her mobility, it was up to her son—and next in line to the throne—Prince Charles to step in for her when she decided not to attend the Commonwealth Day church service held today.

Several members of the royal family gathered at Westminster Abbey in London for the return of the Commonwealth gathering after last year’s event was canceled due to the COVID-19 pandemic.

Prince William and Duchess Kate were two of the first to arrive for the afternoon service—both dressed in complementary blue tones. The Duchess of Cambridge chose a regal shade for her bespoke Catherine Walker coat dress, Lock & Co hat, and Rupert Sanderson shoes.

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Duke and Duchess of Cambridge Commonwealth Service
Photo: Getty

It is thought that the Cambridges wore the color not just as a nod to the Commonwealth flag, but also as a show of support for Ukraine (as it appears in the country’s national flag). Kate’s sapphire jewelry, which once belonged to Princess Diana, included the same necklace and earrings she wore when meeting President Volodymyr Zelenskyy and his wife, Olena Zelenska, at Buckingham Palace in October 2020.

“Fantastic to come together to celebrate #CommonwealthDay and modern, vibrant and diverse communities across the globe at Westminster Abbey today,” Kate and William wrote on Twitter.

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Camilla, Duchess of Cornwall, also chose a royal hue for her look: a vibrant purple coat dress and matching hat. It is the fourth time she has worn the color for Commonwealth Day.

Prince Charles and Camilla Commonwealth Service
Photo: Getty

Greetings from the Cambridges were noticeably warmer than during the last Commonwealth service in 2020, when the couple were seen giving cold shoulders to Prince Harry and Duchess Meghan at their final royal engagement. This time, Kate was seen kissing Camilla on both cheeks, and William shook his father’s hand as they smiled and chatted before taking their seats near the abbey’s altar.

British prime minister Boris Johnson, the queen’s cousin Princess Alexandra, hundreds of dignitaries, and more than 600 schoolchildren also attended the event. The Duke and Duchess of Gloucester were scheduled to attend but canceled last week after the duke tested positive for COVID-19.

The Right Honourable Lord Bishop Sentamu, Britain’s first Black archbishop, gave a passionate address to the congregation, and there were musical numbers by the London African Gospel Choir, Mica Paris, and Emeli Sandé.

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The queen watched a live broadcast of the service from her Windsor Castle home. In a message written for the 2.5 billion citizens of the Commonwealth—the “family of nations”—she renewed her pledge to devote her life to service, saying, “In this year of my Platinum Jubilee, it has given me pleasure to renew the promise I made in 1947, that my life will always be devoted in service.”

She added, “In these testing times, it is my hope that you can draw strength and inspiration from what we share, as we work together towards a healthy, sustainable and prosperous future for all.”

This article originally appeared on Harper’s BAZAAR US.