Katie and Kevin Tsang met in in 2008 while studying at the Chinese University of Hong Kong. Since then they have lived on three different continents and travelled to over 40 countries together. They currently live in London.

Kevin was born in Copenhagen and grew up in Atlanta, Georgia. Some of Sam Wu's experiences are based on Kevin's childhood (he's feeling much more confident now). Katie was born and raised in Southern California. She has previously worked at Booktrust, the UK's largest children's reading charity, and also writes YA fiction as Katherine Webber.