Famke Janssen (X-Men, Nip/Tuck) is joining Gemma Arterton and Jeremy Renner in Hansel and Gretel: Witch Hunters. Tommy Wirkola (Dead Snow) will be directing the film, described as “…a dark action movie that picks up with the fairy tale siblings years after the traumatic childhood incident has turned them into bounty hunters."
Production on this film begins in March, and while they have not specified what role Janssen will be taking, I'll venture a guess and say witch. We'll definitely have more cast and plot information once production starts.
**Update- Deadline confirms... witch: "Famke Janssen will play the leader of the witches..."