Valance was born in Fitzroy, Victoria to a Serb father, Rajko Vukadinović, and an English mother, Rachel (née Stephens) of Spanish descent. Her father was a musician, playing the piano, and a model in his younger years in Belgrade. Her mother, whose father was a relative of Benny Hill, was a model in the UK. She has two sisters, Coco and Olympia. The latter is an actress who played Paige Smith in Neighbours. All three sisters hold dual Australian-British citizenship. Valance grew up in Melbourne and moved to the UK when she was 18. After two years in the UK, she moved to Los Angeles, where she spent seven years.