While Peter Capaldi has already committed to starring on "Doctor Who" for his third year, the Twelfth Doctor says he isn't so sure if he'll stick around beyond that.

Promoting the "Doctor Who Christmas Special," Capaldi told Telegraph that next year could be his last as The Doctor:

"This could be my final year – it’s terrifying. I love Doctor Who but it can be quite an insular world and I do want to do other things. There will come a time when this is over. But I knew that when I started. I was thinking about my regeneration scene from the outset. That’s my terrible melancholic nature. When you accept the job you know there’ll come a day, inevitably, when you’ll be saying goodbye."

It seems Capaldi's involvement in "Doctor Who" beyond 2016 is up in the air -- but while we've got him, check out the Doctor Who Christmas Special -- "The Husbands of River Song" -- when it airs December 25 at 5:15 p.m. ET on BBC One.