'Call the Midwife' is to enter a "new era".
Ben Caplan, who plays Police Constable Peter Noakes, claims the popular period drama's move towards the 1960s marks a new start for the show after Jessica, who played lead character Jenny Lee, quit the series after three years.
Ben told Digital Spy: "It will be different not having her around, but I'm excited to see how it changes ... particularly as we're moving into a new era, we're moving into the '60s.
"The show's going to change a lot moving into a different decade, and if there's going to be a big change, I think it's the right time to do it."
Jessica left the drama in the third series finale last month as Jenny quit quit midwifery to begin working in a Marie Curie cancer hospital and started a new life with future husband Phillip Worth (Stephen Ashfield).
Ben claims the cast were supportive of Jessica's decision to leave and insists the departure of such a central character will not hinder the show's success moving forward.
Ben mused: "It was sad to see her go, but she wanted to move over to pastures new. I also respected her decision that she'd done the show and got what she needed to get out of it, so it was time to move on.
"It'll be interesting to see how we progress, but it will progress! The show is obviously bigger than one element of it."
'Call the Midwife' will return for a Christmas special this year and a fourth series in 2015.
Tagged in Jessica Raine