Olivia Newton-John is an Australian pop singer and actress. She is a four-time Grammy award winner who has amassed five No. 1 and ten other Top Ten Billboard Hot 100 singles and two No. 1 Billboard 200 solo albums. Eleven of her singles and 14 of her albums have been certified gold by the RIAA. Her music has been successful in multiple formats including pop, country and adult contemporary and has sold an estimated over 100 million albums worldwide. She co-starred with John Travolta in the film adaptation of the Broadway musical Grease, which featured one of the most successful film soundtracks in Hollywood history.