Miriam Margolyes is set to guest star in the 'Call the Midwife' Christmas special.
The 76-year-old acclaimed actress has bagged the role of Sister Mildred, a forthright and indefatigable sister from the Order, in the festive episode at the end of the year.
The bolshie medic arrives unexpectedly at Nonnatus House with four Chinese orphans - who were found abandoned in Hong Kong after fleeing China and are being adopted in the UK as part of the World Refugee Project - in tow.
But with Christmas preparations in full flow and the midwives busy caring for the expectant mothers of Poplar, these unexpected visitors cause both joy and chaos.
Miriam isn't the only new cast member joining the show as Fenella Woolgar has jumped on board as Sister Hilda, Ella Bruccoleri will play postulant Sister Frances and Georgie Glen will portray Miss Higgins, the surgery's new receptionist.
Dame Pippa Harris, Executive Producer, said: "We are all thrilled to be filming once again with our beloved team of midwives and nuns from Nonnatus House.
"This year we have the additional treat of Miriam Margolyes as a guest star and cannot wait for audiences to see her as the formidable Sister Mildred.
"We hope that viewers will also warmly embrace our two new Sisters, played by Fenella and Ella, and the fabulous Georgie Glen who plays Doctor Turner's indomitable new receptionist, Miss Higgins.
"It's an honour to have such skilful, and charismatic actors joining the cast and bringing Heidi Thomas's wonderful scripts to life."
The Christmas Special will also see Trixie Franklin (Helen George) return to Poplar just in time to cover for the Sisters as they leave for the Mother House.
Heidi Thomas, Creator, Writer and Executive Producer said: "It is an immense privilege to be starting work on series eight of 'Call The Midwife', and we can't wait to share the events of 1964 with our loyal and passionate audience.
"People often ask me how we can keep coming back year after year, but the answer is simple - we never run out of stories, and we never run out of love."
Tagged in Helen George