ROLES AREN'T FOR KEEPS ON ‘CROWN,' EVEN NEWCOMER PRINCESS DI

For viewers, “The Crown” offers a peek into a modern royal family’s life and times, or at least an engaging dramatization. For the cast, it’s meant the lofty equivalent of gig work as the Netflix series ticks through the decades.

Claire Foy played Britain’s young Queen Elizabeth II for the first two seasons, with Olivia Colman stepping in to chart her middle years last season and in the 10 new episodes out Sunday. Imelda Staunton ascends to the throne for the final two chapters.

When Diana Spencer makes her pivotal entrance this season, largely set in the 1980s, it’s Emma Corrin in the part opposite Josh O’Connor’s Prince Charles. Corrin’s job is one and done: Elizabeth Debicki takes over in seasons five and six as the bound-for-tragedy Princess Diana, opposite a new, yet-to-be announced Charles.

A role in “The Crown” is akin to a relay-race baton destined to be handed off, said Helena Bonham Carter, back for her second whirl as tempestuous Princess Margaret. The actor is sandwiched between Vanessa Kirby (seasons one and two) and Lesley Manville, who will take Margaret across the finish line.

“I’m very sad that it’s over, but it’s time that she was played by somebody else at some point.... She’s just a great gift of a part,” Bonham Carter said during a joint interview with Colman and Tobias Menzies, returning as Prince Philip.