Better known under his birth name Robert Wyatt (from his mother's name Honor Wyatt), Robert was the natural son of George Ellidge, who was at that time married to another woman. Robert became officially Robert Ellidge (or Robert Wyatt Ellidge) at the age of 6 when his parents could finally marry and set up home together in 1951.
Robert did, however, revert to his first name Wyatt for most of his musical career.