As for who producers are considering as heir to the throne? The biggest rumour is that Imelda Staunton, who played Dolores Umbridge in the Harry Potter franchise, is in talks to play Queen Elizabeth II.
After a source whispered the name to Deadline, however, Netflix denied the reports, saying "We are currently filming season 4 of The Crown but have not commissioned any further seasons as yet, therefore any news on casting remains pure speculation."
Another name that's been thrown about is none other than Helen Mirren, who has played Queen Elizabeth II before in 2006's The Queen and did such a good job at her portrayal of HRH, she won Best Actress at the Oscars.
Better yet? "She loves the show," according to The Crown's creator Peter Morgan, who teased Mirren as Colman's replacement in August, though he noted he hadn't yet run it past her.