Fast Freddie, The Widow and Me stars Fox as Jonathan Donald, a wealthy car salesman who is found guilty of drink driving.
He ends up receiving a community service order in the run up to Christmas and has to spend time at The Moonbeam Club, a support centre for young adults.
After clashing with the group's leader Laura, played by Wallander star Sarah Smart, Jonathan's attitude begins to change when he meets terminally ill club member Freddie (Jack McMullen). Jonathan ends up vowing to give Freddie, who has spent his life in care homes, the perfect Christmas.
Fox has previously starred as James Hathaway in Lewis and has appeared in movies such as Elizabeth: The Golden Age and Becoming Jane.
The cast of the film also includes Tamzin Outhwaite, David Westhead, Bill Paterson, Marian McLoughlin, Davood Ghadami and Judy Flynn.
The drama's writer Christopher Dunlop said: "I've always wanted to write about the magic of Christmas colliding with the way we torment ourselves trying to make that one day perfect. Fast Freddie, The Widow and Me creates an idyllic family Christmas from the most unlikely collection of characters, who in the process rediscover faith in life, love and hope for the future."
Fast Freddie, The Widow and Me, which is produced by STV, is currently being filmed in London.