Played by award-winning actress Imelda Staunton, she's pictured wearing a very regal combination of pearls with a pussy bow blouse. Her facial expression is rather sombre – an early sign, surely, of drama to come in season five.
The first-look image was shared on Twitter with the caption: "An early glimpse of our new Queen Elizabeth II, Imelda Staunton."
Staunton, known for playing the villainous Dolores Umbridge in the Harry Potter films and her Oscar-nominated performance in Vera Drake, succeeds Claire Foy and Olivia Colman in the period drama's top role.
The show's final cast switch also sees Elizabeth Debicki (Widows, Tenet) take over from Emma Corrin as Princess Diana, Jonathan Pryce (The Two Popes, Evita) succeed Tobias Menzies as Prince Philip, and Lesley Manville (Phantom Thread, Mum) follow in Helena Bonham Carter's footsteps as Princess Margaret.
It's been rumoured, meanwhile, that Dominic West (The Pursuit of Love, The Affair) is taking over from Josh O'Connor as Prince Charles.
Seasons five and six of The Crown are expected to delve into the breakdown of Charles and Diana's marriage, the tragic death of the Princess of Wales, and the Queen's working relationships with Prime Ministers John Major and Tony Blair.
However, Morgan has since extended the story into a sixth season. "It soon became clear that in order to do justice to the richness and complexity of the story, we should go back to the original plan and do six seasons," Morgan told Deadline last year. "To be clear, Series 6 will not bring us any closer to present-day — it will simply enable us to cover the same period in greater detail."