Answer
In the Star Wars films, Mark Hamill's character, Luke Skywalker, is closely related to Carrie Fisher's character, Princess Leia Organa. They are twin siblings, born on the planet of Tatooine to Anakin Skywalker and Padmé Amidala. In the original trilogy, Luke and Leia are unaware of their relationship, but they eventually learn the truth and become close allies in the fight against the Galactic Empire.