The 82-year-old actor has revealed how he and his Romancing The Stone co-star, now 72, fell for each other during filming for the 1984 film while he was separated from then-wife Diandra Douglas.
In an extract from his memoir One Helluva Ride shared by PEOPLE magazine, he wrote: "The chemistry I had with Kathleen Turner was so strong, audiences have been certain for years that we were in a relationship together while making the film.
"We both denied it through Romancing The Stone, Jewel of the Nile, War of the Roses, and even while doing press a few years ago for The Kominsky Method.
"The official story went as follows: Yes, we confessed, we had amazing chemistry. Yes, we were both, as Kathleen said, 'terrible flirts,' and yes, we were both tempted, but nothing ever happened between us.
"That was a lie."
Douglas explained that the lie was "meant to protect my wife and son", and they "told the world for 40 years".
He continued: "Kathleen and I never hit a rough spot. We found each other first as friends, then as co-stars, and finally as lovers.
"Following an exhausting day of shooting in the jungle, we'd go out and have a meal, or head out with the group and afterward I would sneak into her hotel room after everybody was asleep.
"There were no cameras in elevators, no assistants using cell phones to take pictures."
They didn't tell any of their castmates or director Bob Zemeckis, but the "magic spell of the set" was broken when his wife and their son Cameron came to visit the set in Mexico and she "grew suspicious".
Douglas has recalled how Diandra told Turner that they were "still married" as she saw their separation differently.
He added: "After that visit, Kathleen and I ended things, and I went back to Diandra. I did it for Cameron, but we shouldn't have gotten back together. After that first split it was never the same between us ever again."
As Douglas referenced, Turner - who also appeared with him in the likes of the War of the Roses and The Jewel of the Nile - kept up their public story as she claimed she had "hope for" something romantic between them at one point.
She told Closer magazine: "I was yearning, but he was still married to (to his first wife Diandra Luker)... although they were separated, and so I thought there was hope for me."
9°C