Renee Bailey (Mood) and Natalie Quarry (Doctors) will play the new pupils, Joyce Highland and Rosalind Clifford. Both young characters are excited to embark on the new chapter in their careers together, even sharing a room in Nonnatus House.

Joyce hails from Trinidad and has set her sights on becoming Matron of a British hospital. She's smart, hardworking and kind-hearted, despite a traumatic past that the BBC hints will eventually come to light.

Rosalind may seem naive at times but she is warm, passionate and funny, and has an inner strength that will lead her to make some "life-changing decisions."

The new series is set in the year 1969. With more babies being born in hospital than ever before, there is extraordinary pressure on maternity beds across the country. But thanks to the hard work of Nonnatus House and the popularity of home births under the auspices of the Sisters, Poplar is coping better than most.

Beyond the midwifery, there will be stories from within the Sylheti and Nigerian communities and from around the docks. Poor housing poses complex social and health challenges to the Nonnatus team, and issues surrounding Cerebral Palsy, Congenital Hip Dysplasia, Tetanus, Porphyria and TB are explored.

All the regular cast will return, including Judy Parfitt as Sister Monica Joan, Jenny Agutter as Sister Julienne, Laura Main as Shelagh Turner, Helen George as Trixie Aylward, Cliff Parisi as Fred Buckle, Stephen McGann as Dr Turner, Linda Bassett as Nurse Crane.

Of the new series, Heidi Thomas OBE, creator and writer, says: “After so many years, our much loved regular characters are like family to me - and our wonderful fans so often tell me that they feel the same. I know they will be as thrilled as I am that series 13 is full of beautiful moments that celebrate the young, the old, and the precious ties that bind them.

"After Trixie’s spectacular wedding, the Nonnatus House community feels more tightly-knit than ever, but life in Poplar has never been a fairy tale. As 1969 unfolds we will see change and challenge rock the world of our beloved nuns, nurses, medics, and midwives.

"Newcomers Joyce and Rosalind arrive with much to learn, and much to give. And yet even as man prepares to walk on the moon, we see them grappling with life’s eternal questions. Who are we? What is love? And where do we belong?”

Series 13 of Call the Midwife will consist of a 90 minute Christmas 2023 special, followed by eight episodes in 2024 for BBC One and iPlayer.

In 2021, the RTS celebrated 10 years of Call the Midwife with series writer Heidi Thomas and cast members Helen George, Leonie Elliott and Jenny Agutter. Watch it back here.