MyAnna Buring, Adelayo Adedayo, Ian Hart and Kerrie Hayes have been added to the cast of BBC thriller The Responder.
They join The Hobbit star Martin Freeman in starring in the programme, which is set in Liverpool.
Filming of the series begins on Monday.
Freeman portrays Chris across six night shifts as an urgent response police officer.
The Responder is based on the experiences of officer-turned-writer Tony Schumacher.
He said: “I’m so incredibly fortunate to be writing for a cast as amazing as the one we’ve assembled for The Responder.
“From legends at the top of their game, to young talents who are legends in waiting.
“It’s a writer’s dream come true.”
Rita Tushingham, David Bradley and Warren Brown will also star in the programme.
Executive producer Mona Qureshi said: “The Responder is a completely unique take on modern policing and Tony Schumacher gives us in Chris a heartbreakingly honest portrait of a man coming undone by the pressures around him.
“We’re so excited to see Martin Freeman in this extraordinary role and for [director] Tim Mielants to bring the night-streets of Liverpool to vivid life.”