Call The Midwife favourite Jessica Raine has said she will be "blubbing" along with the rest of the TV audience when the series returns after she bowed out of the show.
The actress, who has been seen as the drama's Jenny Lee since the programme launched, is moving on to "pastures new" and was seen for the last time as the third series reached its finale.
Programme-makers have reassured viewers her character will continue to narrate the stories, inspired by the memoirs written by Jennifer Worth, with the the voice of veteran star Vanessa Redgrave returning once again.
Jessica said: "It's been a real privilege to help bring Jenny Lee's story alive and amazingly satisfying to see how the public have embraced the series, but as is in keeping with Jenny's story, it's time for me to explore pastures new.
"So it is with a head full of wonderful memories that I leave my friends and a show that I know will continue to go from strength to strength. I too will be tuning in to series four and blubbing with the nation."
A spokeswoman for the show said: "Like Jenny Lee herself, Jessica is keen to explore new ventures. Jennifer Worth worked as a midwife for just a few years, but the nuns remained in the East End for another quarter of a century.
"Her friendship with the Order lasted a lifetime, and inspired her to immortalise them in her memoirs. Call The Midwife will carry on with that fascinating and emotional story, celebrating the people of Poplar, and the much-loved residents of Nonnatus House.
"Vanessa Redgrave will continue as narrator, maintaining our link with the very special author of the books that inspired us. We wish Jessica all the love and luck in the world as she cycles off into her future."