We last saw Rix on our TV screens when his character Matthew Aylward left Poplar and headed to New York amid a flurry of financial difficulties, and while Call the Midwife is a medical drama too, Rix will be much more hands-on in this role.

With this being quite the jump between characters, Rix spoke exclusively with RadioTimes.com about his decision to join Casualty.

"I had lunch with the executive producer and we talked about the character in a lot of detail," he explained.

"We spoke for about three hours and I just thought she was wonderful, and I really liked her vision for the role, for the role within the series.

"The way the series was going, it was just modern, relevant, exciting, and just something I really wanted to be involved in."

Rix's character, Flynn, has been described as "a man with a purpose and with a fierce resolve to make a difference", as he joins the NHS fresh from a tour of duty, something Rix researched heavily ahead of filming for the series.

He told RadioTimes.com: "I managed to do some some fascinating research with some special forces soldiers and they were extremely generous with their time and the level of information that they imparted to me, not specifically about military stuff, but I asked them very blunt questions about what their relationship was like to death, mortality, how that made them feel about their families, what it was like when they would go away on tour.