Starring Poppy Montgomery, the unauthorized biopic based on a biography by Sean Smith, chronicles the British author’s struggles from single mother on welfare to become one of the world’s wealthiest women. The Lifetime Original Movie premiering Monday, July 18 at 8p ET starts with her modest upbringing and follows her rise to fame and wealth as the author of the beloved Harry Potter children’s books, with over 400 million copies sold across the globe resulting in a billion-dollar film franchise.