The new Duke and Duchess of Edinburgh (formerly Earl and Countess of Wessex) were among the senior royals to attend, and Sophie was spotted sharing a sweet exchange with her brother-in-law, Charles on camera.
The interaction sparked a reaction from viewers on Twitter, with one commenting: “Love how Duchess Sophie playfully bumps King Charles. Bet he asked her how she was enjoying her new title that he just bestowed.”
Another wrote: “Duchess of Edinburgh’s side touch to King Charles, she’s adorable.” A third added: “They obviously have a great relationship.”
It comes after the King conferred the Dukedom of Edinburgh on his younger brother, Prince Edward, which coincided with his 59th birthday on Friday.
As a consequence of the change, Edward and Sophie’s 15-year-old son, James, Viscount Severn, is now known as the Earl of Wessex.
Buckingham Palace previously announced Edward would eventually one day succeed his father as the Duke of Edinburgh – but not until after the death of both Philip and the Queen.
Edward and Sophie made their public debut with their new titles on Friday, attending a reception in Edinburgh to mark one year since the Scottish capital welcomed the first Ukrainians to the city.
In a speech, the new Duke of Edinburgh said: “Thank you for welcoming us to Edinburgh today on, indeed, a very special and very overwhelming day for now my wife and duchess.”
Sophie looked elegant in a white coat by Proenza Schouler and a matching hat by Jane Taylor for the Commonwealth Day service in London.
The Edinburghs were also joined by the Prince and Princess of Wales as well as the Princess Royal and Vice Admiral Sir Tim Laurence.
In a speech at the service, the King paid tribute to his “beloved mother”, describing how Commonwealth Day was a moment of pride for the late Queen Elizabeth who “dedicated her long and remarkable life” in service to the “Commonwealth family”.