Netflix confirmed that actress Emma Corrin will join the "Season 4" action, which is played by Lady Diane Spencer, the first wife of Prince Charles.
Corrin, who participated a bit in the British drama "Grandchester", and will soon be featured in Epic's PennyWorld series, said she was "not delighted" to join actors.
"I was stuck to the exhibition from the first episode, and thinking that I am now joining this incredibly talented actor's family is simply surrealistic," she said in her release. "Diana's Princess was an icon and her influence on the world remains profound and inspiring. Enabling her to study it through Peter Morgan's writing is the most exceptional opportunity, and I will strive to make it fair."
The Crown Season 3 is launched on Netflix in 2019.
In the new season, Oscar Olivia Colman will take over the role of Queen Elizabeth from Claire Foy.
Tobias Menzis and Elena Bonham Carter will also join the acting studio, playing old versions of the characters created by Matt Smith and Vanessa Kirby.