Doctor Who star Matt Smith has told fans: "You'll forget about me!"
He was asked at the Comic-Con event in San Diego, USA, why he's leaving.
He said: "I kind of figure it's been four years - the best four years. It's been wonderful. It's been a privilege to work under Steven Moffat, but, you know, when you gotta go, you gotta go. Trenzalore calls.
"It wasn't an easy choice, it wasn't an easy decision to come to. But, I don't know, you can't play it forever."
It was announced in June that Matt would leave Doctor Who at the end of the year.
Matt added: "And look - they'll get someone amazing, they'll get someone brilliant to do it, they really will.
"And that's the great thing about the show. It continues and the strength of it survives.
"It will get better and it'll get bigger and it'll keep going - and you'll forget about me."
That final answer triggered a chorus of no's from the audience!