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"It became a little embarrassing for me," she said on BBC's "The Graham Norton Show," after acknowledging how many news outlets picked up the story featured in her new memoir, "The Princess Diarist."
When British host Norton suggested that now Ford will have to talk about the alleged affair for the rest of his life, Fisher said, "and now I feel more guilty."
In her memoir, Fisher, 60, wrote that the affair took place over three months while filming "Star Wars: Episode IV A New Hope" in 1976.
Ford, 74, was married to his first wife at the time, Mary Marquardt. The two split in 1979.
The film, released a year later, starred Fisher as the passionate Princess Leia and Ford as the wise-cracking, yet reluctant hero Han Solo.
“It was so intense,” she told People magazine. "It was Han and Leia during the week, and Carrie and Harrison during the weekend."
Fisher was 19 at the time, while Ford was 33.
About their romance four decades ago, Fisher added, "I was so inexperienced, but I trusted something about him. He was kind."
A rep for Ford did not return ABC News' request for comment about Fisher's claims. Still, the actress told People he knew about the upcoming book.
The two recently reunited on-screen again as Leia and Han in last year's "The Force Awakens."