Call the Midwife returns to BBC One with the third episode of the season and Rosalind Clifford (played by Natalie Quarry) has to put her knowledge and skills to the test when she delivers a disabled baby. Meanwhile, a gas explosion at an apartment block shocks the community, with Joyce Highland (Renee Bailey) at the centre of the drama.
Meanwhile, Sister Julienne (Jenny Agutter) calls on Trixie Aylward’s (Helen George) managerial skills when she attends a meeting with Dr Threapwood (Timothy Harker) to discuss the renewal of their contract with the council.
Most of the regular cast will be back including Linda Bassett as Phyllis Crane and Judy Parfitt as Sister Monica Joan. Laura Main returns as Shelagh Turner with Stephen McGann as her on-screen husband, Patrick.
Cliff Parisi and Annabelle Apsion are back as Fred and Violet Buckle, with Georgie Glen and Rebecca Gethings back as Millicent Higgins and Sister Veronica.
Here is all you need to know about the guest cast for episode three.
Alf Cottered is played by David Troughton (Image: BBC)
Dr Threapwood – Timothy Harker
Dr Threapwood is played by Timothy Harker, a Welsh actor who started acting as a middle-aged man.
His first screen role was in 2015 in the horror short I Shall Visit.
He went on to star in Peaky Blinders, Black Doves and The Agency.
PC Gibbs – Ben Simpson
PC Gibbs is played by Ben Simpson, who has previously starred in Holby City, The Cazalets, The Bill and The Phoenix and the Carpet.
Mr Mackintosh – David Blair
Mr Mackintosh is played by David Blair, who left the Guildhall School of Music and Drama in 1995.
He is best known for his role as Stuart in Island and as Herbert Batty in Dalziel and Pascoe.
Miss Jenkins – Lisa Coleman
Miss Jenkins is played by Lisa Coleman, a 54-year-old English actress known for playing Jude Korcanik in Casualty and Cam Lawson in The Story of Tracy Beaker.
She has since taken up volunteering as an occupational therapist in a psychiatric unit.
She is the sister of TV and film actress Charlotte Coleman and her mother Ann Beach, was also an actress.
Alf Cottered – David Troughton
Alf Cottered is played by David Troughton, a 74-year-old English actor known for his stage roles in Shakespearean works.
He also played Dr Bob Buzzard in A Very Peculiar Practice and Ricky Hanson in New Tricks.
The star has a famous family as both his father, Patrick, and nephew, Harry Melling, worked as actors.
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Alexa Davies and Garmon Rhys as Norma and Don (Image: BBC)
Nerys Anderson is played by Georgia Landers (Image: BBC)
Debbie Anderson – Alyssa Monteith
Debbie Anderson is played by Alyssa Monteith, a child actress who is playing her first major role in Call the Midwife.
Nerys Anderson – Georgia Landers
Nerys Anderson is played by Georgia Landers, an actress and theatre star known for Dungeons & Dragons: Honour Among Thieves.
She also had small roles in The Girl Before, Casualty and Press.
Don Lasley – Garmon Rhys
Don Lasley is played by Garmon Rhys, who viewers may recognise as PC Ryan Davies in Hidden.
He also played Patrick in Gangs of London and Dewi in Enid a Lucy.
Norma Lasley – Alexa Davies
Norma Lasley is played by Alexa Davies, a 29-year-old Welsh actress who played Aretha in Raised by Wolves.
She also played a young Rosie in Mamma Mia! Here We Go Again, and Meg in Dead Pixels.
Call the Midwife airs on Sundays on One at 8pm