Meeting a Time Lord can be scary and Katherine Jenkins says she was really nervous before appearing in Doctor Who.
The opera singer stars alongside Matt Smith and Karen Gillan in this year's Christmas special.
She told the Radio Times that her nerves were "far worse" than normal before the show.
She said: "I just thought 'I'd love to give it a try'. But I'm the first to say that I really don't consider myself an actress."
The singer plays a character called Abigail in the Christmas special.