If You Love Me Let Me Know. 1974. Words and Music by John Rostill. Featrured here, and recorded on Interfusion Records, by Olivia Newton-John. Olivia Newton-John, AO, OBE (born 26 September 1948) is an English-born Australian singer, songwriter and actress. Born in Cambridge, England, to a Welsh father, Brinley ("Bryn") Newton-John, and a Berlin-born mother, Irene Helene (née Born), the eldest child of the Nobel Prize-winning atomic physicist Max Born.