Scan of January edition of Empire UK (page 16):
http://i.imgur.com/7CKqcOi.jpg
(Bullet point #4)
Transcribed:
4. Really He's Not A Clown
Poulter was cast as Pennywise, the ancient alien spider-clown villain in Cary Fukunaga's mooted adaptation of Stephen King's It.
But when Fukunaga exited the project, so did Poulter.
"My loyalties had to be with Cary. His vision for It was brilliant, dark, really layered and original. I'm gutted it's not happening."