David Threlfall is to play a hard-working detective in a new BBC serial - his first role following his long running stint as dodgy layabout Frank Gallagher in Shameless.
The actor leads a cast which also includes former Being Human star Russell Tovey in a gritty new whodunnit thriller for BBC1, What Remains.
Threlfall has been filming his final episode of Channel 4's Shameless this week after playing dysfunctional Frank for a decade.
The 59-year-old star plays Detective Inspector Len Harper who is about to retire but is determined to unravel the death of a young woman whose remains are found in a loft, two years after she disappeared.
During his investigation the lives of residents - played by Tovey, Stephen Mackintosh and Victoria Hamilton among others - in four adjoining flats come under the spotlight. The BBC said it was a "thrilling state-of-the-nation whodunnit".
The four hour-long episodes have been written by Tony Basgallop, whose recent projects have include heist drama Inside Men and biopics of Boy George and Hughie Green.
He said: "The key to writing and casting What Remains has been in ensuring that we had the right chemistry between the characters. Fortunately we've landed a cast with the quality and experience to pull the audience in any direction we choose to take them."
Executive producer Hilary Salmon said: "Tony is one of the stand-out British dramatists currently writing for television and we are thrilled to be making his intriguing new murder mystery.
The series has begun filming in London.