Call The Midwife stars Helen George and Jack Ashton have told of how having a baby has changed their feelings about the series.

George and Ashton, who are in a relationship off-screen, announced the birth of their daughter Wren in October after filming had finished on the Christmas special.

Ahead of the seasonal episode of the popular BBC One drama, George – who plays midwife Trixie Franklin – said she feels more emotional about the programme now she is a mother.

She said: “I definitely felt more emotional about it.

Call The Midwife
Call The Midwife (BBC/Neal Street Productions/Nicky Johnston)

“I mean I love babies, and I’ve always found these scenes emotional, but it’s something else watching it this time, I was like ‘oh my God’.”

Ashton, who plays Rev Tom Hereward, said that fatherhood has “enlightened” him, and that a lack of sleep has helped him channel his emotions on-screen.

He said: “To be honest, I don’t really get involved with the child birth aspect of this show.

“But yes, it’s certainly enlightened me a lot, and it absolutely changes you as a person.”

Asked if he will request to be in more scenes with babies now, Ashton joked: “Or less!”

He added: “I think, to be honest, going back when Wren was so young and having no sleep certainly changed my acting.

“It’s certainly a lot easier to act emotion when you haven’t slept for 48 hours, so I’ll keep that one as I go through my career.”

Call The Midwife
Jack Hawkins as Christopher and Helen George as Nurse Trixie in Call The Midwife (BBC/Neal Street Productions/Sophie Mutevelian))

This year’s Call The Midwife Christmas special will see the beloved characters battling through the coldest winter on record in 1962/63, which brought the country to a standstill.

The midwives struggle to provide the best care for their patients, and Jennifer Kirby – who plays Nurse Valerie – explained that there are “many, many repercussions” from that.

She added: “Valerie helps out a young mother give birth in the weather conditions in a tiny little caravan and there’s lots of fallout from that.

“And then there’s also another storyline with Jenny Agutter (Sister Julienne) and guest starring Anita Dobson (Mabel), which is brilliant by all accounts. And dealing with a loss in the family and what that entails.”

Stephen McGann, who plays Dr Turner, said that this year’s Christmas special is a “bit different from last year”.

“That’s really a lovely thing to come home and it hits you with a bang, it’s colder than the others, definitely colder,” he added.

Call The Midwife
(L-R) Jennifer Kirby as Valerie, Jack Ashton as Rev. Tom Hereward, Linda Bassett as Nurse Phyllis and Victoria Yeates as, Sister Winifred (BBC/Neal Street Productions/Sophie Mutevelian)

He praised the show’s writer and creator Heidi Thomas – his wife – who “isn’t scared to go to those places” in the Christmas special, which he said is “deeply emotional”.

Thomas said she tries to add more of an element of hope in the Christmas episodes of the programme, but that the show must largely stick to its course.

She said: “I always think you have to give people Call The Midwife – you have to give them what they get in the main series, it’s not a completely different genre because it’s on at Christmas.

“I think at Christmas, what I’m very concerned with is to leave people with some hope.

“Because quite often we end our episodes on a sad note, or a realistic note, or a truthful note, and that’s not always happy or uplifting, and I do think Christmas is the one time, however many tears you shed, or however much these actors put you through the emotions, you have to end with hope.”

The Call The Midwife Christmas special will air on BBC One on Christmas Day.