JK Rowling has been awarded a gold Blue Peter badge by the programme's presenters and has been interviewed by 25 children for tonight's show.

The author will appear this evening in one of only two UK interviews before the final Harry Potter book The Deathly Hallows is released tomorrow.

During the show, host Gethin Jones gives Rowling the show's highest accolade.

She acted surprised at the offer and said: "You have no idea what that means ... Thank you very, very much."

A group of 25 children also got to ask her questions after winning the privilege in a competition run by Blue Peter.