The BBC adaptation of David Walliams' book will air on New Year’s Day, and viewers would be forgiven for not knowing who is portraying the vicar.

With a balding head, glasses and false teeth, the villainous vicar looks totally different to the 59-year-old who’s playing the role.

The wicked character Miss Dandy - who runs an old people’s home called Twilight Towers - is played by none other than Jennifer Saunders.

The evil Miss Dandy poses as a vicar in order to win the trust of families with elderly relatives, before forging their wills and swindling the inheritance.

And it’s not hard to see how the on-screen families are convinced by the vicar, as the award-winning comic looks a world away from her usual self after the shocking transformation.

Returning to our TV screens this Christmas, Jennifer’s role will be a start contrast to her famous French and Saunders sketch.

Speaking about the BBC adaptation, Jennifer said: “I love playing villains - they’re so much more interesting than nice people. It’s so easy, it comes naturally.

"Miss Dandy is the sort of person you’d hope would never be in charge of an old people’s home, but great fun because of that.

"She’s a self-serving psychopath with very few redeeming features… I think the fact that her tool of choice is a cattle-prod says a lot about her mentality.”

David Walliams co-wrote the script for the hour-long adaption, and also stars in it himself.

Grandpa’s Great Escape will air on BBC One on New Year’s Day at 6.55pm.