This bench is more Charlie Sheen than Katharine Hepburn.

A Manhattan park bench donated by the late actress’ heirs has become a recent hotbed for raunch and pot, with wanton women engaging in midafternoon sex acts as perverted men stare while smoking weed, according to residents.

“I was watching from across the street, and I couldn’t believe it,” Sherrill Kazan said of the behavior she witnessed at 4:30 p.m. Friday.

Kazan is president of a volunteer group that maintains the 1.5-acre Dag Hammarskjold Plaza on East 47th Street and Second Avenue, near the legendary star’s former home.

Later that evening, three men were arrested for drug possession.

News of the defiling comes as the park’s caretakers consider showing outdoor movies there.

But, because the NYPD does not issue “sound device” applications for after 8 p.m., Kazan says the group is exploring technologies that would allow films to be shown in daylight.