The delay is similar to the pause between the second and third seasons of the series, when Olivia Colman, Tobias Menzies and Helena Bonham Carter replaced Claire Foy, Matt Smith and Vanessa Kirby as Queen Elizabeth, Prince Philip and Princess Margaret, respectively.
There was a two-year break between the airing of the second and third seasons of The Crown, with season two dropping in December 2017 and season three premiering in November 2019.
Production on season four began before season three premiered, with season four expected to air on Netflix later this year.
The fourth season is expected to take place during the 1980s, introducing Princess Diana, played by Emma Corrin, and Margaret Thatcher, played by Gillian Anderson. Seasons five and six will take the story into the 2000s.
The cast of the British royal family drama will change again between the show's fourth and fifth seasons, with Imelda Staunton set to assume the role of Queen Elizabeth and Lesley Manville to play Princess Margaret. It's not yet clear who will take over the role of Prince Philip.
Creator Peter Morgan recently revealed that he'd returned to his original plan to have the series run for six seasons instead of an abbreviated five-season run, which he had said at the time was the "perfect time and place to stop." But, Morgan clarified, "season six will not bring us any closer to present day - it will simply enable us to cover the same period in greater detail."