Olivia Colman stars as Elizabeth, with main cast members Tobias Menzies, Helena Bonham Carter, Josh O'Connor, Marion Bailey, Erin Doherty and Emerald Fennell all reprising their roles from the third season.

Additionally, Charles Dance returns in the season's first episode and Claire Foy reprises her role as Elizabeth in a cameo flashback scene.

Events depicted include the courtship and wedding of Prince Charles and Lady Diana Spencer,[4][13] their 1983 tour of Australia and New Zealand,[3][14] the Falklands War,[15] Michael Fagan's break-in at Buckingham Palace,[16] Lord Mountbatten's funeral,[17] the Princess of Wales's appearance at the Barnardo's Champion Children Awards, and at the end of the series, Thatcher's departure from office, as well as the marital difficulties of Charles and Diana.

[41] In September 2019 Gillian Anderson, who had been rumoured since that January to be in talks to portray Margaret Thatcher in the fourth season, was officially confirmed for the role.

[48][49] Season 4 of The Crown received universal acclaim from critics upon release, with widespread praise directed towards the performances of Olivia Colman, Tobias Menzies, Helena Bonham Carter, Gillian Anderson, Josh O'Connor, and Emma Corrin for their portrayals of Queen Elizabeth II, Prince Philip, Duke of Edinburgh, Princess Margaret, Margaret Thatcher, Prince Charles, and Lady Diana Spencer, respectively.

[51][52][53] Writing in The Atlantic, Shirley Li describes the drama as "sharper than ever" and "splashy" but observes that, in contrast to the first three seasons, the fourth criticizes the Queen for her "ignorance" and "stubborn devotion to tradition.

"[54] In the Evening Standard, Katie Rosseinsky wrote that the season's episodes are "dizzyingly beautiful and staggering in scope", and highlights the outstanding performances of Anderson and Corrin as Thatcher and Lady Diana, respectively.

[55] In The New Zealand Herald, university professor Giselle Bastin described the season as "a masterly portrait of the turbulent 1980s" and complimented the production standards, casting, and acting.

[56] BBC's arts editor Will Gompertz gave the series a rating of 4 out of 5, praising Corrin and Bonham Carter, but criticizing Anderson's performance for "forever craning her neck from side-to-side as if scanning for a tasty lettuce leaf, while over-egging her Thatcher impression to such an extent she is close to unwatchable at times.

"[57] In a critical review, Dominic Patten of Deadline Hollywood complimented the earlier seasons but said that the fourth had "substantially tweaked timelines" and was "sub-standard soap," and that, despite Colman's performance, some of the other characters were like "Spitting Image live-action caricature[s].

[72] Their schedule was never revised to accommodate Prince William, and the sheep station was arranged for them in advance by the former Australian Prime Minister, specifically so that the couple could be with their son each night.

[68] According to Dickie Arbiter, the meeting in which Sir John Riddell, the Prince of Wales's private secretary, questions Diana's mental fitness before her solo trip to New York never happened.

[74] Vickers suggested that almost all the details concerning how visitors are treated at Balmoral are inaccurate, and noted that the Thatchers' first visit is depicted out of sequence with Mountbatten's funeral.

He added that, as a member of an aristocratic family, Diana was already familiar with royal etiquette, and therefore would not have needed the intensive lessons given by Lady Fermoy that were portrayed in the show.

[74] Vickers says that, in reality, it was the Queen's press secretary who took it upon himself to pass his own views about the Prime Minister to the media, and he was forced to leave the palace as a consequence.