Although many people didn't realize it at the time, Newton-John was playing much younger than her real age when she appeared in 'Grease'; she was over 30 when she took the part. After having a child during the mid-80s and attempting a musical comeback, she was approaching 40 and struggling to keep up with the new generation. She needed a change.
Newton-John's life was fundamentally changed by a breast cancer diagnosis in 1992. She would beat this encounter with the disease, but her approach to her career changed, and she moved more into activism and advocacy than she had done previously. She's barely appeared as an actress in the past thirty years, but has consistently released new music, having returned her country music roots in more recent years. She was still touring until 2017 when she announced the was facing a second battle with cancer.