And then there were nun…
Two midwife nuns are leaving Call the Midwife this Christmas, having served the people of Poplar diligently for the past four years.
Sister Hilda, played by Fenella Woolgar, is already absent by the time the festive special kicks off, having been called away for God’s work at the Mother House.
And it won’t be long before young Sister Frances, played by Ella Bruccoleri, is packed off to join her after falling off her bike in the snow during a birth emergency.
By the end of the BBC1 feature-length special, to air in time-honoured fashion on Christmas Day, the young nun has disappeared to the coast for a lengthy spell of recuperation.
Fans of the show will know that the Mother House is a place from where nuns never return to Poplar - and Sister Frances will be no exception.
One insider said: “Ella and Fenella are off doing other things now - but that doesn’t mean they won’t come back again at some point. They’ll both be missed.”
Actress Jenny Agutter, who plays Nonnatus House head nun Sister Julienne, agreed: “The door is always open.”
Both actors joined the long-running series in 2019.
Their departures are offset by the return of original cast member Helen George as reformed alcoholic Trixie Franklin. The actress was written out during the last series as she took maternity leave for her second child.
Over Christmas, after a long courtship, she and Matthew Aylward (Olly Rix) will finally get engaged.
The Christmas storylines will feature the ongoing fallout from the Thalidomide scandal, which has left young Susan Mullucks struggling to be included by other kids and turned her dad into an alcoholic.
Another issue-led plot sees a young, abandoned pregnant woman being cast into the street as she goes into labour.
But festive cheer is provided by a fun talent contest organised by Fred Buckle (Cliff Parisi) - Poplartunity Knocks.
Viewers will be treated to dishy Matthew singing a duet with nurse Nancy Corrigan (Megan Cusack) while receptionist Miss Higgins (Georgie Glen) attempts to delight the audience by playing her recorder - with less success - and the Turner children are joined by little Susan to perform as singing snowmen.
