Olivia Newton-John is an Australian singer, songwriter, actress, and activist. She is a four-time Grammy Award winner who has amassed five number-one and ten other Top Ten Billboard Hot 100 singles, and two number-one Billboard 200 solo albums. She is best known for her role as Sandy in the musical film Grease and for her 1981 single 'PHYSICAL'. Newton-John has been a long-time activist for environmental and animal rights issues.