The Oscar-winning Titanic star was a surprise addition to the festival's line-up on Sunday.
“I’ve always dreamed of being on the show one year and I’m so excited to be on this year’s Christmas Special."
It sounds like CBeebies might have a few more grown-up viewers than usual next week.
The Strictly Come Dancing champion will be the first celebrity to tell a story using British Sign Language.
"This is me, I am George. I can’t wait to be your friend.”
Watch a preview of the actor's CBeebies' debut here.
"I’ve always said I’ve wanted to use my platform and voice to make a difference."