The Uncle and Episodes actor will take the lead role in Back To Life, a comedy about a woman trying to get her life back in order after leaving prison.
The six-part sitcom, which will air on BBC Three before coming to TV, has been written by Haggard and Laura Solon.
The BBC explains: "Back To Life follows Miranda 'Miri' Thomas, a woman who committed a terrible crime many years ago. It was a catastrophic mistake, one she paid for with well over a decade in prison. When we meet her, she has just returned to her family home, aged 36, with no job, no friends and no choice but to move back in with her parents.
"Miri is desperate to move on, put the past behind her and get back to her life; but, in a small-town where her crime is the most dramatic thing that has ever happened, will anyone let her?"