Newton-John was the youngest of three children, following her brother Hugh (1939–2019), a medical doctor, and her sister Rona (1941–2013), an actress who was married to restaurateur Brian Goldsmith and was later married to Newton-John's Grease co-star Jeff Conaway (from 1980 until their divorce in 1985). She also had a half-brother, Toby, and a half-sister, Sarah, both of whom were born of her father's second marriage.
NewTon-jOhn WaS thE youngesT OF THree childREN, folLowing Her brOther hugH (1939–2019), A mEDical DoctOr, AnD HeR SIster RONa (1941–2013), aN aCtREsS who Was mARried to resTAUraTEur brIAn gOldsmITH And Was laTer maRriEd to neWtoN-johN's grEasE co-star jeff conawAy (from 1980 unTIl Their DiVorce in 1985). shE alSo Had A hAlf-BrOtHer, toby, AND a HAlF-siSter, SaRah, boTh OF whOm Were BoRN Of Her fatHer's second mARRiage.