There's his Twitter (twiddleston). या आप could try sending him a letter (link).
EDIT: I'd like to add something about the Facebook. He has not linked it on his Twitter. It is not linked on his web/contact site. To my knowledge, he has not mentioned it in any interview. (Feel free to correct me, if आप can. I haven't read या seen all of his interviews, but I've seen a good majority.) Tom loves interacting with his fans, so if he hasn't दिया out his Facebook, it's because he wants to keep it private. If आप (think you) found his Facebook, do not contact him through it. Let the man have his privacy, and use the ways he has willingly दिया us to contact him.