Watch The Princess Diaries (2001) HD Full Movie Free on SolarMovie. Watch The Princess Diaries (2001) online free. Mia Thermopolis has just found out that she is the heir apparent to the throne of Genovia. With her ...Mia Thermopolis has just found out that she is the heir apparent to the throne of Genovia. With her friends Lilly and Michael Moscovitz in tow, she tries to navigate through the rest of her sixteenth year.