One Direction have joined other stars in penning pages of a new children's book for children in need.
Each star has written a page based on reading only the last line of the previous page. Other stars taking part include Kylie Minogue, Paul McCartney, and Wayne and Coleen Rooney.
One Direction appear as a band of frogs called 'Pond Direction'!
The story follows a girl that is half human and half dinosaur,
See more about 'The Curious Tale of Fi-Rex' at http://www.bbc.co.uk/newsround/34441400