Michael Douglas confirms secret affair with Kathleen Turner on 'Romancing the Stone' set

Michael Douglas is confirming a rumor that has followed him around for decades.

In an excerpt from his upcoming memoir, "One Helluva Ride," the 82-year-old actor revealed that he and Kathleen Turner had an affair while filming "Romancing the Stone," a rumor they denied for over 40 years.

"Kathleen was smart, funny, and sexy with a deep, sultry voice that became her signature," he wrote in an excerpt obtained by People. "I instantly liked her, and we were immediately attracted to each other."

He went on to say that although he was married to Diandra Luker at the time, "things at home were in a bad place" and both he and Luker "were both having extramarital affairs."

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Douglas admitted he and Turner had an affair while filming "Romancing the Stone." (20th Century-Fox/Getty Images)

Douglas wrote that he left home to film the 1984 movie "still technically married, but separated," and that while audiences were "certain for years that we were in a relationship together" while making the movie, they denied it, even through the making of the sequel and years later when they reunited on "The Kominsky Method."

The two would tell the public that while they "had amazing chemistry" and were "both tempted," they never acted on their feelings.

"The truth is that during the production of Romancing the Stone, Kathleen and I fell hard for each other and began a relationship," he wrote. "It wasn’t a fly-by night affair; it grew naturally from how closely we were working together, how much pressure we were under, how much we respected and cared for one another, and how attracted we were to each other. Like every other guy in the world at the time, I was knocked sideways by Kathleen."

He noted that the two of them kept their affair a secret for 40 years in order to protect Luker and their son, Cameron.

Turner and Douglas kept their affair a secret for 40 years to protect his son and ex-wife. (John Lamparski/WireImage)

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The affair was kept a secret from everyone, including the film's director, Bob Zemeckis, and their co-star, Danny DeVito, with Douglas adding the two would go to dinner together after filming or that he "would sneak into her hotel room after everybody was asleep."

"There were no cameras in elevators, no assistants using cell phones to take pictures," he said. "As Jack and Joan were falling in love, Kathleen and I were keeping the chemistry alive."

Douglas and Turner were falling in love as their characters were doing the same on screen. (Sunset Boulevard/Corbis via Getty Images)

Turner and Douglas decided to end things after Luker visited them on set with Cameron, "and made it clear to her [Turner] that we were still married."

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After stories began circulating of Douglas' new admission, Turner said in a statement to People, "Good heavens what a fuss about something 40 years ago! I love Michael and I look forward to enjoying the book."

"Romancing the Stone" follows Turner as Joan, a romance novelist who travels to Columbia to rescue her sister from smugglers and meets bird hunter Jack Colton, played by Douglas, who agrees to help her.

Douglas and Luker finalized their divorce in 2000, after which he married Catherine Zeta-Jones. (Arnold Jerocki/Getty Images)

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Lurker eventually filed for divorce in 1995, and after 23 years of marriage, their divorce was finalized in 2000, with the actor writing, "After that first split it was never the same between us ever again."

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He went on to marry actress Catherine Zeta-Jones in November 2000. He has since welcomed two children with the "Wednesday" actress: son Dylan, 26, and daughter Carys, 23.

Lori A. Bashian is an entertainment news writer at Fox News Digital.