Carrie Fisher had an "intense" three-month affair with Harrison Ford.

Carrie Fisher

Carrie Fisher

The actress was just 19-years-old when she had a 12 week dalliance with her 'Star Wars' co-star in 1976.

She told People magazine: "It was so intense. It was Han and Leia during the week, and Carrie and Harrison during the weekend."

Writing in her book The Princess Diarist, she added: "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."

And the 60-year-old star later took to Twitter to insist she wouldn't be going into any more details about what happened.

She wrote on the microblogging site: "I couldnt get twitter working on my new phone so I've been away during this out of context book excerpt time ... I would never talk about how someone was in any furniture - chair, bed, coffee table or otherwise."

Meanwhile, Carrie previously opened up about the chemistry between the pair.

She shared: "I actually recently found my diaries from this [time] ... It had some memories in it ... I wonder it too, so when I found the journals I looked. I haven't looked all the way through it but I must say it seemed to be trending in that direction ...

"Well when I went on the film I really thought, I saw him and he looked like a movie star. I met him in LA and read with him and stuff and was too nervous to see him. So when we got on the set I saw him and he was sitting in the Millennium Falcon ... and I thought he looked like one of those movie stars which was not how Mark [Hamill] and I appeared."