Evanna Lynch for Butler scandal

Evanna Lynch has signed up for a scandalous role in upcoming crime drama Monster Butler.

The 20-year-old Harry Potter star - known for playing dippy Luna Lovegood - is to take on the role of Fiona Carrick-Smith, the daughter of an aristocrat, who is seduced by her wise old butler who is in fact a confidence trickster, played by 68-year-old Malcolm McDowell.

Monster Butler is based on the true story of Roy Fontaine, aka Archibald Hall, who was a bisexual jewel thief, con man and serial killer. Fiona's reckless behaviour after falling for her confidant is destined to end in tragedy, according to The Hollywood Reporter.

The film will chronicle Fontaine's journey from petty thief as a teenager to a serial killer. Until he died in 2002, he was the oldest person serving a whole life sentence in prison.

Gary Oldman is already on board to play a creepy taxidermist, who becomes one of Fontaine's partners in crime.

Lord Of The Rings star Dominic Monaghan has been cast as Fontaine's lover and The Borgias' Joanne Whalley has also signed up for the film.

Douglas Rath is directing the movie, which begins shooting on location in Scotland and London this month.