A ‘charming but complicated’ new doctor is about to arrive in BBC’s Casualty – and he’s played by a very familiar face to Call The Midwife fans.

Olly Rix, who played Matthew Aylward in 32 episodes of the beloved TV series, will take on the role of Clinical Lead Flynn Byron in the upcoming new Casualty miniseries Internal Affairs, which starts in March.

The character comes to the ED with a backstory involving trauma as he’s fresh from a tour of duty in the military. He sets about trying to make a change in a department weighed down by bureaucracy, while also grappling with his personal demons and a deception that threatens to be his undoing.

‘It’s been a pleasure to join the Casualty cast in such a dynamic role,’ Olly Rix said.

‘Flynn crashes into the world of it from a very different background, resulting in a complex and exciting story in Internal Affairs and beyond. It’s a brilliant new chapter for the show and I am excited for the audience to get to know Flynn.’

Casualty’s Executive Producer, Roxanne Harvey, told us that, ‘Flynn’s journey promises to resonate with viewers, exploring the often emotional toll of working in the NHS, the cost of making tough decisions, and the possibility of redemption when you’re confronted with the consequences of your actions.’

Flynn is not the only new face in the ED in March, as acclaimed actor Robert Bathurst, known to viewers for Cold Feet, Doctor Who and Downton Abbey, will take on the guest role of Russell Whitelaw, who is the kind of domineering and highly skilful surgeon who is bound to ruffle feathers.

Robert Bathurst commented that the realistic hospital set had brought its own challenges. ‘The Emergency Department film set was just like being in a hospital – I kept getting lost!’ he said.

‘They built an operating theatre especially for this block of stories so all of us, actors and crew, were on a voyage of discovery. As always with Casualty there were brilliantly qualified advisers on hand to make it seem as real as possible.’

Casualty continues to be essential viewing on Saturday evenings on BBC1 and on iPlayer, with the current box set, Public Property, dealing with topics ranging from Nicole (Sammy Dobson)’s post-postpartum psychosis to Dylan (William Beck)’s struggles to protect his career after serious allegations from a patient.