With the latest rumoured cast member being Dominic West.
Though it is not quite a done-deal, a source has told Variety that West is currently in late-stage discussions for the role of Prince Charles for both seasons, taking over from Josh O'Connnor.
The actor, who is known for his roles in The Wire and The Affair, is yet to publicly comment, however, now that the cat's out of the bag, let's take a look at all the cast members that have been confirmed to appear in the fifth and sixth seasons.
Elizabeth Debicki as Princess Diana
The Australian actress was confirmed to take on the coveted role earlier this year.
"Princess Diana's spirit, her words and her actions live in the hearts of so many. It is my tru privilege and honour to be joining this masterful series, which has had me absolutely hooked from episode one," she said in a statement announcing the news.
Imelda Staunton as Queen Elizabeth II
British actress Imelda Staunton, known for her role as Dolores Umbridge in the Harry Potter series, is set to depict Queen Elizabeth II after Olivia Colman.
"I have loved watching The Crown from the very start. As an actor, it was a joy to see how both Claire Foy and Olivia Colman brought something special and unique to Peter Morgan’s scripts. I am genuinely honoured to be joining such an exceptional creative team and to be taking The Crown to its conclusion," she wrote.
The series' showrunner Peter Morgan also took to praising the actress upon confirming the news.
"I’m absolutely thrilled to confirm Imelda Staunton as Her Majesty The Queen for the fifth and final season, taking The Crown into the 21st century. Imelda is an astonishing talent and will be a fantastic successor to Claire Foy and Olivia Colman," he said.
Jonathan Pryce as Prince Philip
While he's come to be known for playing 'villains' like Game of Thrones' High Sparrow, Oscar-nominated Welsh actor Jonathan Pryce will play Prince Philip in the upcoming final seasons, succeeding Tobias Menzies and Matt Smith.
Lesley Manville as Princess Margaret
Another Oscar-nominated star joining the cast is Lesley Manville, who will be taking over the role of the Queen's sister, Princess Margaret, from Helena Bonham Carter and Vanessa Kirby.
Excited over the score, she shared a statement that read: “I could not be happier to be playing Princess Margaret. The baton is being passed on from two formidable actresses and I really don’t want to let the side down. Furthermore, to play siblings with my dear friend Imelda Staunton will be nothing short of a complete joy.”