The couple reveal the impact the Christmas special has on their own festivities.
After Call the Midwife Star Stephen McGann confirmed he and his show creator wife Heidi Thomas "always watch" the BBC One special "together", Heidi has admitted the show "ruins" their own Christmas.
The couple, who live together in Hertfordshire and have one son Dominic, 20, revealed on ITV's Lorraine show the impact the popular TV series has on their own lives.
"It’s all for the audience and our fans," said Heidi, 58. "...It’s something that’s the same at Christmas - it ruins our Christmas Day because we get so nervous but it’s a sacrifice we’re so willing to make."
Despite social distancing restrictions, this year's Christmas Special is still going ahead - as the cast has been successfully filming.
Speaking about the impact of Covid-19, Heidi said her working partnership with husband Stephen, 57, who plays Dr Turner in the drama, "works really well". As writer and executive producer, she explained, “I feel quite cut off - I think many of us at this time can feel very cut off from our place of work. Everything’s channeled into this (computer) screen but he comes home from work and he brings me pictures on his phone or tells me the news and I feel more involved than I would probably if I wasn’t married to Dr Turner."
How did Call the Midwife's Stephen and Heidi meet?
Stephen previously lets us in on a few secrets about his marriage to Heidi...
"I was 23, a young actor living in London when I went to an audition for Heidi's play. I read the script on the train to Liverpool, the story of a family going through crisis. It was amazing, searing and beautiful. I tried to imagine the woman who wrote it and though it was obviously someone quite mature, maybe a wizened academic. When I saw Heidi, this tiny little girl - the same age as me - I fell madly in love.
He continued, "I used to say that marrying Heidi had killed my chances of working with one of the country's leading writers. No one would cast me in her work, as people would say, "Oh you're Heidi's husband!"
"When she rang me to ask if I'd play Dr Turner in Call the Midwife, I was studying at Imperial, having a great old time. I said, 'Heidi! I'm at University preparing my dissertation!' She said, 'No, it's perfect. It's only a few days here and there.' Then she said the immortal line, 'It probably won't run longer than six episodes!'
How do the Call the Midwife stars balance work with marriage?
Stephen, who stars in the period drama alongside actress Jenny Agutter, explained, "Call the Midwife has been a wonderful shared adventure, but our roles are very separate. Heidi is principally pre- and post-production. She generally writes at home but also has a lot of meetings. She hardly ever comes on set, which is the place I live. We're not bumping into each other, but we've shared the ups and downs, the details... and the gossip.
"We always watch the show together. What's sweet is that out son will watch it with us when he's home. We tell him he doesn't have to, but he says, 'No, this is what you folks have been doing all year.' He tells us not to give him any spoilers.
Speaking about their home lives, he added, "We live in a beautiful but ordinary world. When we married we moved to rural Essex and we brought our son up there, and now we've nipped over the border and bought an old chapel in the countryside. Showbusiness and London is something we go into - and then come home again.
"I put the success of Call the Midwife down to the genius that is my wife. She's funny and intelligent, with this deep well of sincere feeling that she knows how to bring out. She speaks to people's hearts. And she spoke to mine."
Call the Midwife Christmas Special returns to BBC One 25th December; Flesh and Blood by Stephen McGann is out now (Simon & Schuster).