Call the Midwife is set to welcome two new characters in the upcoming Christmas special of the BBC period drama.
Student midwives and roommates, Joyce Highland and Rosalind Clifford, are Poplar's latest additions and are played by actors Renee Bailey and Natalie Quarry respectively.
Joyce, who hails from Trinidad, is described as "hardworking, fiercely bright and deeply kind," but hides a traumatic past that she can't conceal forever. Meanwhile, Rosalind is "young, warm, passionate and funny" and is "naive at times, but with an inner steeliness."
Writer and creator Heidi Thomas said: "Newcomers Joyce and Rosalind arrive with much to learn."
Executive producer Dame Pippa Harris added: "They're a wonderful addition to the show.
"I can't wait for the audience to meet Joyce and Rosalind and to follow their journeys, by bicycle, through the streets and lives of Poplar's residents."
Filming for the upcoming festive special began in May, with the show's official Instagram account sharing the news with behind-the-scenes snaps of the cast.
One post included photos showing Max Macmillan and Stephen McGann, who play Timothy and Patrick Turner, wrapped up in winter coats whilst sitting in the front seats of a car.
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In the caption, the drama's social media account revealed that the actors had been filming driving sequences at the Royal Dockyard in Chatham, Kent.
"Filming is off to a WONDERFUL start, and it was great to be back at the dockyard, where the official Call the Midwife tour takes place," the caption read.
Since then, the show has been keeping fans up to date with more photos from the set and even teased the emotional Christmas special with a video that showed the three youngest Turner children, Angela, Teddy and May, playing in the snow.
Alongside the clip of young actors Alice Brown, Edward Shaw and April-Rae Hoang, the show's Instagram team wrote: "Filming for this year's seasonal story is going BRILLIANTLY – laughter, joy and family. With perhaps a tissue or two."
So, what can fans expect from the upcoming Christmas special?
Speaking about the festive episode in an interview with RadioTimes.com, Stephen said: "It has a different feel; it's a different audience, people are staying home with their families and so it's a different vibe. It's also the thing that brings us into a new season.
"It has all those elements and over the years, we've all gotten used to that rhythm," he added.
Season 13 is set in 1969 and tells stories from within the Sylheti and Nigerian communities and from around the docks. The synopsis teases: "Poor housing continues to blight areas of Poplar presenting complex social and health challenges to the Nonnatus team."
Issues surrounding Cerebral Palsy, Congenital Hip Dysplasia, Tetanus, Porphyria and TB will also be explored.
While fans will be looking forward to seeing their favourite characters back on their screens, one person who won't be returning to Poplar is Leonie Elliott, who plays Lucille Anderson.
The actress left the drama in season 12 when her character left London for Jamaica to recover from her nervous breakdown.
In a statement posted on Instagram, Leonie thanked fans for their support over the years. "Thank you all for embracing Lucille and rocking with me on this journey, it is with a heart full of love and appreciation that I embark on pastures new," she wrote.
"Having spent 6 years on a truly wonderful show, with a fantastic team I have fallen deeper and deeper in love with Lucille. I feel honoured to have represented the pioneering Windrush generation and their incredible impact on British society."