Michael Douglas revealed Charlie Sheen taped a sign on their “Wall Street” co-star Sean Young’s back that said “Biggest c–t in the world” on the set of the 1987 film.

In his new memoir, “One Helluva Ride,” Douglas recalled how Young — who played his onscreen wife — “caused a lot of problems on set” and “had a terrible relationship” with the entire cast and crew, especially Sheen.

When Douglas noticed the sign on Young’s back, he pulled it off and told her to “forget” what it said.

However, someone on the crew told Young what Sheen wrote.

“She had every right to be furious,” Douglas, 82, said in his book.

Douglas recalled that Young kept clashing with director Oliver Stone, who decided to give her only line in a horse stable scene to Daryl Hannah.

In response, Young allegedly told Stone, “If I don’t have any lines in the scene, then what’s the point of me being here?”

Stone, 80, agreed with Young, 66, and fired her on the spot, Douglas said.

Hannah, according to Douglas, also had a tough time filming the crime drama, which boasted a male-dominated cast.

The “Steel Magnolias” star butted heads with Stone, Douglas explained, since they “had their own unique style and ways of working,” as well as “their own strong opinions.”

Douglas claimed cinematographer Bobby Richardson urged Stone to recast both Young and Hannah, but Stone refused until he fired Young.

“Oliver would later say he wished he had fired both,” Douglas wrote, noting the director ended up cutting most of Young’s scenes from the movie.

Douglas also wrote in his book that Stone often focuses on “male-centered stories” in his films, even with the strong performances by his female stars.

Douglas won an Oscar for his role as duplicitous stockbroker Gordon Gekko in “Wall Street.”

He earned his first Academy Award over a decade earlier, as a producer of the 1976 Best Picture winner “One Flew Over the Cuckoo’s Nest.”

During an interview with TCM’s Alicia Malone earlier this year, Douglas credited Stone for pushing other actors — like James Woods in “Salvador” and Tom Cruise in “Born on the Fourth of July” — to give their “best performance” in his films.

“His record of successes with actors is quite impressive,” Douglas said. “So I’m deeply, deeply appreciative of the fact that it gave me part and the fact that he pushed me to another level.”

“One Helluva Ride” is out now.