Preparations are underway for a big kids' party at Buckingham Palace to celebrate the Queen's 80th birthday.
Loads of characters from children's books are taking part in Sunday's bash, including Tracey Beaker, Paddington Bear and Harry Potter.
They're putting on a show for the Queen and her guests - 2,000 kids and 1,000 adults picked by a national ballot.
The grounds of the palace are being transformed into a theme park featuring lots of scenes from kids' literature.
You might also recognise one of Newsround's presenters, as our very own Lizo is playing a part.
As part of the party, up to 800 libraries will be taking part in a Literary Long Weekend to promote reading for fun.
The Queen will send a special message to all libraries taking part in the event, as will Tracy Beaker.
Although the Queen's real birthday was on 17 April, she gets another official birthday in June.
That's so outside parties in her honour are more likely to have nicer weather.