It's already more-or-less secured Jeff Bridges as exorcist Master Gregory and Julianne Moore as witch queen Mother Malkin, and it now looks as if The Seventh Son has found its young leads, in relative newbies Sam Clafin and Alicia Vikander.

Clafin will play Tom, Luke Skywalker to Bridges' Ben Kenobi, learning the ropes of witch-hunting and coming to terms with his supernatural abilities. And Vikander's role is Alice, daughter of Malkin, who may or may not be a chip off the old block. The film is an adaptation of The Spook's Apprentice, the first of Joseph Delaney's best-selling kids series The Wardstone Chronicles.

Alex Pettyfer and Jennifer Lawrence were being mentioned in connection with the roles at one point, and other contenders at this week's tests included Caleb Landry-Jones, James Frecheville, Imogen Poots and Gabrielle Wild. Clafin (Pirates of the Caribbean: On Stranger Tides) and Vikander (Beloved) were the two that most impressed the suits though, and will be in front of Sergei Bodrov's cameras when shooting starts.

According to Variety, the film doesn't actually, technically have the green light at this point, but that's surely a formality now. Warners have their collective eye on a 2013 release.