Michael Douglas confirms 40-year-old secret: he and Kathleen Turner had a real affair on 'Romancing the Stone'

For forty years, Michael Douglas and Kathleen Turner told the same story: yes, the chemistry was real, but nothing happened. Now, at 82, Douglas has put the truth in print.

In an excerpt from his upcoming memoir, 'One Helluva Ride' — published by People ahead of the book's release — Douglas confirms that he and Turner began a romantic relationship during production of the 1984 hit 'Romancing the Stone,' a rumor both had denied through subsequent films and decades of interviews.

The truth is that during the production of Romancing the Stone, Kathleen and I fell hard for each other and began a relationship. 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.— Michael Douglas, actor and author

Douglas describes the secrecy as deliberate and total. The affair was kept from everyone on set — including director Bob Zemeckis and co-star Danny DeVito. According to Douglas, the two would go to dinner together after filming or he 'would sneak into her hotel room after everybody was asleep.' He credits the era's lack of surveillance for making it possible: 'There were no cameras in elevators, no assistants using cell phones to take pictures.'

At the time, Douglas was married to Diandra Luker, though he writes that he left home to film 'still technically married, but separated,' and that both he and Luker 'were both having extramarital affairs.' He describes his immediate attraction to Turner in the memoir.

Kathleen was smart, funny, and sexy with a deep, sultry voice that became her signature. I instantly liked her, and we were immediately attracted to each other.— Michael Douglas, actor and author

The relationship ended on set when Luker visited with their son Cameron, an encounter Douglas says 'made it clear to her [Turner] that we were still married.' He writes that after that moment, 'it was never the same between us ever again' — referring to his marriage to Luker, which formally ended in divorce in 2000 after 23 years.

The denial held through the making of the sequel, 'The Jewel of the Nile,' through 'The War of the Roses,' and as recently as their reunion on 'The Kominsky Method.' Douglas writes that the two publicly maintained they had 'amazing chemistry' and were 'both tempted' but never acted on it. He says the secret was kept specifically to protect Luker and Cameron.

Turner's response, when the excerpt began circulating, was brief and characteristically direct.

Good heavens, what a fuss about something 40 years ago! I love Michael, and I look forward to enjoying the book.— Kathleen Turner, actress

'Romancing the Stone' follows Turner's character Joan, a romance novelist who travels to Colombia to rescue her sister from smugglers, and Douglas's Jack Colton, a bird hunter who agrees to help her. The on-screen romance between the two leads was widely credited as central to the film's success — audiences, Douglas writes, 'were certain for years that we were in a relationship together.' They were right.

Douglas married actress Catherine Zeta-Jones in November 2000, the same year his divorce from Luker was finalized. 'One Helluva Ride' is out this month.

Why it matters — One of Hollywood's most persistent 'will-they-won't-they' rumors turns out to have been true — and the memoir reveals the specific, human reasons a secret that size was kept for four decades.

Reported by foxnews.com, people.com, tvinsider.com, hollywoodreporter.com