The relationship between Carrie Fisher's Princess Leia and Harrison Ford's Han Solo was one of the driving forces of the original Star Wars trilogy, which carried over to this year's Star Wars: The Force Awakens. Carrie Fisher now reveals that, nearly 40 years ago on the set, as a 19-year-old actress, she actually had a real-life love affair with Harrison Ford, who was then a 33-year-old married father with two children. This revelation comes as part of an excerpt of her upcoming book The Princess Diarist. broke the news, with the actress detailing her affair to the website, as People Magazine gets ready to publish an exclusive excerpt from the book in Friday's issue. The actress revealed that she had a three-month affair with Harrison Ford, who was married to Mary Marquardt at the time, while production was under way on the first Star Wars movie. Here's what Carrie Fisher had to say about this love affair she had kept secret for 40 years.

RELATED: Mark Hamill Celebrates Carrie Fisher's Hollywood Walk of Fame Induction
"It was so intense. It was Han and Leia during the week, and Carrie and Harrison during the weekend."

The actress says she decided to open up about the affair after discovering "angst-ridden journals" she kept while filming in London. She went on to write The Princess Diarist, which will be published on November 22. She also revealed that Harrison Ford was given advanced notice about the book, and received an early copy, but the actor wouldn't respond to People's request for comment on the story. She revealed that they spent their first night together after attending a birthday party for director George Lucas. Here's what she had to say about how she was filled with "self-doubt" about the affair, on the set of Star Wars: Episode IV - A New Hope.

"I looked over at Harrison. A hero's face - a few strands of hair fell over his noble, slightly furrowed brow. How could you ask such a shining specimen of a man to be satisfied with the likes of me? I was so inexperienced, but I trusted something about him. He was kind."

Carrie Fisher added that the affair ended after the production wrapped on the first Star Wars movie. Harrison Ford got divorced from his first wife Mary Marquardt, before marrying E.T. screenwriter Melissa Mathison in 1983, who he was married to for 21 years before their divorce in 2004. The actor has been married to actress Calista Flockhart since 2010.