“I am thrilled to be joining The Firm for the next instalment of The Crown,” O’Connor said. “Seasons three and four will follow some of the most turbulent events in the Prince of Wales’ life and our national story and I’m excited to be bringing to life the man in the midst of it all. I’m very aware it’s a formidably talented family to be joining, but reliably informed I have the ears for the part and will fit right in.”
Bailey, who will replace actress Victoria Hamilton in the role, said that the new cast “have a tough act to follow” but added that it was “a gift to be playing the fascinating and greatly loved Queen Mother”.
The casting additions means the line-up for seasons three and four is almost complete – although some key characters are still unannounced.
Sign up to the Radio Times newsletter for the latest TV and entertainment news