Pharrell Williams has joined forces with Penguin Young Readers to release four picture books, with the first - based on his hit track Happy - available September 22.

The book features photographs of children across cultures celebrating what it means to be happy, and Williams commented 'I'm humbled by the global success of Happy, but especially in awe of the song's young fans. My collaboration with Penguin allows me to continue a dialogue with these children in a fresh, new way. We're both committed to feeding the curiosity of young minds with imagination'.