Carrie Fisher has claimed she had an “intense” affair with Harrison Ford during the making of Star Wars.

The actress said she had a three-month romance with the Han Solo star – a married father-of-two at the time – which she kept secret for 40 years.

Carrie, who played Princess Leia in the original Star Wars trilogy, told People magazine: “It was so intense. It was Han and Leia during the week, and Carrie and Harrison during the weekend.”

Carrie Fisher with Star Wars co-stars Mark Hamill, and Harrison Ford in 2015 Carrie Fisher with Star Wars co-stars Mark Hamill and Harrison Ford in 2015 (Richard Shotwell/Invision/AP)

Carrie was 19 at the time of the alleged affair in 1976, 14 years younger than Harrison, then 33.

In an excerpt from her memoir, The Princess Diarist, Carrie said she and Harrison spent their first night together following a birthday party for Star Wars director George Lucas.

She wrote: “I looked over at Harrison. A hero’s face – a few strands of hair fell over his noble, slightly furrowed brow.

Harrison Ford and Carrie Fisher on the set of The Stars Holiday TV special in 1978Harrison Ford and Carrie Fisher on the set of The Star Wars Holiday Special in 1978 (George Brich/AP)

“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 and Harrison reunited on screen in 2015′s Star Wars Episode VII: The Force Awakens. In the course of the original Star Wars trilogy, Fisher and Ford’s characters fall in love.

Harrison Ford, Carrie Fisher and Mark Hamill in Star Wars (AP/20th Century-Fox Film Corporation)Harrison Ford, Carrie Fisher and Mark Hamill in Star Wars (AP/20th Century-Fox Film Corporation)

Harrison, 74, has been married three times, divorcing his first wife Mary Marquardt in 1979. He separated from his second wife, screenwriter Melissa Mathison, in 2001 and the couple later divorced.

Harrison has been married to Ally McBeal actress Calista Flockhart since 2010. Carrie, 60, was previously married to musician Paul Simon.

The Princess Diarist is released on November 22.