Pharrell Williams and his book publisher have launched a “Happy” campaign for young readers.

Along with Penguin Young Readers, the singer has partnered with FirstBook, a nonprofit literacy organization, to donate up to 50,000 books to children in low-income families. Penguin announced Tuesday that the Twitter hashtag (hash) read Happy had been established for fans to pharrell-turns-40post thoughts or images on why reading makes them “Happy.” Every post shared elsewhere on social media will lead to a donation.

“Every child on this planet deserves to experience the joy of reading,” Pharrell said in a statement issued through Penguin.

Pharrell’s picture book, “Happy,” based on his hit song, comes out next week.