Former Downton Abbey actress Jessica Brown Findlay who played Lady Sybil in the popular period drama, will join Daniel Radcliffe and James McAvoy in a new Frankenstein movie.

McAvoy will play Victor Von Frankenstein, Radcliffe will play Igor (the lab assistant) and Findlay will play a trapeze artist whom Igor rescues.

Speaking about the film at the Toronto Film Festival, Radcliffe said: "It's about two young, brilliant guys pushing each other. Eventually one loses his morality and the other has to bring him back."

In relation to the script by Chronicle's Max Landis, Radcliffe said it's by "far and away the best script [he's] read coming out of a big studio in the time that [he's] been off Harry Potter".

Findlay will first star on the big screen alongside Colin Farrell and Will Smith in Winter's Tale, which opens in February 2014.

Lucky Number Slevin director Paul McGuigan will helm the as-yet-untitled adaptation of Mary Shelley's novel which is due out in the US on October 17, 2014.