Prince William and Duchess Kate are tackling royal duties as a tandem once more.

The Cambridges reunited on the public stage on Sunday afternoon to give thanks to NHS staff for their service amid the COVID-19 pandemic. They attended Queen Elizabeth Hospital in King's Lynn, on what was also the 72nd birthday of the U.K.'s NHS healthcare system.

"Today we mark the 72nd birthday of the NHS, in a year when it was needed more than ever as the nation responds to COVID-19," the Cambridges wrote on social media.

"Whether you are existing staff, former staff members who came out of retirement, volunteers or key workers - we thank you for the resilience, perseverance and hope you’ve shown our nation," the message of thanks concluded.

William & Kate attend first event together post-lockdown

During the visit, William and Kate sat for tea with staff, volunteers, and children at the hospital on what was a sunny afternoon.

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Photos of the event show the Duke and Duchess of Cambridge greeting staff upon their arrival, being presented with three small key rings (gifts for George, Charlotte, and Louis), and enjoying beverages outdoors.

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The Duchess was seen wearing a Beulah London silk dress, according to Hello!.

Prince William & Duchess Catherine resumed in-person duties in June 2020

Though the Duke and the Duchess have made several solo outings since the royals returned to in-person duties, this was the first event they attended as a pair. Most recently, Prince William had visited the Rose & Crown pub on Friday to mark the weekend reopening of U.K. pubs and stores.

Sunday's visit to Queen Elizabeth Hospital, meanwhile, marked the 72nd anniversary of the July 5, 1948, launch of the NHS. Queen Elizabeth Hospital opened in 1980, and it will also celebrate its 40th anniversary later this month, on July 22.

The Duke and Duchess of Cambridge's Instagram post about the afternoon at the hospital is included below.