 Rhys was born in Islington in north London, the son of John Rees (his spelling) and his English wife Emma Percival of Hockerill.Shortly afterwards his father set up in the wine and spirits trade, working for Walter Gilbey in premises in Nott Square, Carmarthen, where before marriage he had been in training for the ministry.The family was in Carmarthen for a number of years, and had a Welsh-speaking maid.