She hailed the communication used during the pandemic that "offers an immediacy that transcends boundaries or division".
"Looking forward, relationships with others across the Commonwealth will remain important, as we strive to deliver a common future that is sustainable and more secure."
The Duke and Duchess of Cambridge looked deeply serious as they appeared in prerecorded segments speaking to medical and charity staff from across the Commonwealth.
William described how the couple had met many healthcare workers this year, the strain etched on their faces with Meghan's interview expected to address her rift with Kate.
The Duchess of Cambridge may also face calls to give evidence to a bullying probe after former aides claimed she witnessed Meghan's alleged "challenging behaviour" — claims the Duchess of Sussex vehemently denies.
Prince Charles and Camilla, Duchess of Cornwall also appeared in the TV special. The Prince of Wales called for the Commonwealth to "offer an example to the world" and highlighted environmental projects including green hydrogen in Australia and sustainable shipping in Barbados.
Charles said that amid the "heartbreak" of the pandemic the "extraordinary determination, courage and creativity with which people have responded has been an inspiration to us all".
The Queen's ailing husband Prince Philip, 99, remains in hospital, where he has been for several weeks. Last week he underwent a "successful" operation for a pre-existing heart condition.
"In Her Majesty's annual Commonwealth Day message, the Queen will pay tribute to the way in which communities across the family of nations have come together in response to the pandemic," a palace statement released before the special read.
It's an action-packed day for royal-watchers, who are nervously awaiting the screening of Harry and Meghan's much-hyped tell-all interview about their dramatic exit from the royal family.
MEGHAN'S TELL-ALL: WHAT TO EXPECT
Meghan and Harry's two-hour interview with Oprah Winfrey will air in the US at noon.
The teasers released for the special so far show Meghan and Harry don't appear to be holding back in their critiques of the British media – and the royal family.
Meghan, who has been hit with historical bullying allegations from the palace in recent days, refers to the royal family as "the Firm" in the latest clip released.
"How do you feel about the palace hearing you speak your truth today?" Oprah asks.
"I don't know how they could expect that after all of this time we would still just be silent when there is an active role that the Firm is playing in perpetuating falsehoods about us," says Meghan.
"And if that comes with [the] risk of losing things … there's a lot that's been lost already."
An earlier snippet showed Oprah asking Meghan: "Were you silent, or were you silenced?"
Another clip showed Harry appearing to take a jab at Charles and the rest of the royal family for not supporting his mother, Princess Diana.
"You know, for me, I'm just really relieved and happy to be sitting here talking to you with my wife by my side because I can't begin to imagine what it must have been like for her [Princess Diana] going through this process by herself all those years ago," he said. "Because it has been unbelievably tough for the two of us, but at least we had each other."
