Kate Waterhouse is a model and journalist, and the daughter of horse trainer Gai Waterhouse and bookmaker Robbie Waterhouse.

Gabriel Marie "Gai" Waterhouse is an Australian horse trainer and businesswoman. The daughter of Tommy J. Smith, a leading trainer of Thoroughbred racehorses, Waterhouse was born and raised in Sydney. After graduating from the University of New South Wales, she worked as an actor for a time, appearing in both Australian and English television series. Having worked under her father for a period of 15 years, Waterhouse was granted an Australian Jockey Club (AJC) licence in 1992, and trained her first Group One (G1) winner later that year.