Actress Laura Main has revealed that Call the Midwife has “expanded” to fill the gap left by Nurse Jenny Lee.

Original star Jessica Raine departed the show at the end of the third series.

Main, who plays Shelagh Turner (formerly Sister Bernadette), told Radio Times: “I wonder if people will think there isn’t a fourth series because it felt so final in so many ways – so many stories were tied up.”

She explained: “Before now, I couldn’t see how it would work, but I think the show has expanded so much and we’ve got to know all the characters and the world they inhabit so much better now over these three series that I think it’ll be more than fine.”

Series 4 is currently filming and will see Linda Bassett (East Is East) and Charlotte Ritchie (Fresh Meat) join the cast as Nurse Phyllis Crane and Nurse Barbara Gilbert.

Discussing what’s coming up for her character, she hinted: “It’s really nice actually. We saw at the end of Series 3 that there was happiness and that is continuing.”

She added: “It became quite all-encompassing, this desire for a family. It wasn’t the happy start to married life they’d hoped for – and adding to that, Shelagh still had a bit of guilt about leaving behind a certain life. But we’re over that now. She’s got what she hoped for and she’s now happily integrated back into that world again. They’ve got a wonderful family unit – Timothy and baby Angela – so things are really very good for them.”

Series narrator Vanessa Redgrave will appear as the mature Jennifer Worth on screen in this year’s Christmas special.

Main teased: “That’s really exciting. Mature Jennifer will be on screen for the very first time. I was really quite moved when I saw that on the page. It’s a new dimension and quite poignant really to see Jennifer Worth – you get to see Jenny Lee, but this is her as she was when she was writing her memoirs.”

> Buy the complete Season 1-3 boxset on Amazon.

Are you looking forward to Series 4? Let us know below…