Potter fans are waking up to great news after JK Rowling revealed she has completed writing book number six.
A message on the author's website on Monday evening said that Harry Potter and the Half-Blood Prince was now with JK's book publishers Bloomsbury.
And even better news is to come, as JK added that she expects the release date of the book to be announced on Tuesday.
The message was locked behind a special door on her website, which could only be unlocked be answering riddles.
JK announced the news on her website
But once fans got past those riddles they could read the message themselves.
In it she said: "I am as happy as I have ever been with the end result. I only hope you feel it was worth the wait when you finally read it!"
The fifth book, the Order of the Phoenix, was finished in December 2002 and was in book shops in June 2003.