The Crown is keeping with the tradition.
On Tuesday, the hit Netflix drama unveiled the first look at Dominic West as Prince Charles and Elizabeth Debicki as Princess Diana.
Both West and Debicki have joined the cast of the fifth season.
Debicki has been set to take over from Emma Corrin, who played Diana in season 4 when she met and married a young Prince Charles (Josh O’Connor) and dealt with the hurdles of worldwide fame.
West is set to take over from O'Connor during the penultimate season of the royal series.
He is currently shooting Downton Abbey 2, which he is also set to appear in.
As previously reported, Imelda Staunton is on board to take over from Olivia Colm as Queen Elizabeth II.
Other new castings for The Crown Season 5 include Jonathan Pryce (Game of Thrones) as Prince Philip and Lesley Manville (Phantom Thread) as Princess Margaret.
Jonny Lee Miller joined the drama as John Major, another pivotal figure in British history.
The Crown Season 5 was set to conclude the series at one point, but the plan changed, and a final, sixth season was officially ordered.
Series creator Peter Morgan revealed the new end date.
"As we started to discuss the storylines for series five, 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," he said in a statement.
The same statement also revealed there would be no significant time jumps to bring us into the present.
"To be clear, season six will not bring us any closer to present day — it will simply enable us to cover the same period in greater detail," added Morgan.
Cindy Holland, who was Netflix's VP of original content at the time the final season order was announced, said the following when the last-ever season was confirmed.
"The Crown keeps raising the bar with each new season."
"We can’t wait for audiences to see the upcoming fourth season, and we’re proud to support Peter’s vision and the phenomenal cast and crew for a sixth and final season."
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Paul Dailly is the Associate Editor for TV Fanatic. Follow him on Twitter.