Police in Los Angeles were “prepared” to arrest Will Smith on battery charges moments after he slapped Chris Rock at Sunday’s Oscar ceremony, the award show’s producer revealed in a new interview.

Producer Will Packer shared the stunning behind-the-scenes details in an interview with ABC that’s set to air in full Friday on “Good Morning America.”

Packer said Rock was in his office shortly after the primetime smackdown when the LAPD officers showed up and offered to take action against Smith. 

“They were saying, ‘This is battery,’ was the word they used in that moment,” Packer said, according to a clip of the interview that aired Thursday on ABC’s “World News Tonight.”

“[The officers] said, ‘We will go get him, we are prepared to get him right now,’” he recalled, referring to Smith. “’You can press charges and we can arrest him,’” the cops added.

But Packer said Rock was “dismissive” of the options and refused to press charges.

The revelation came after the film Academy said it had asked Smith to leave the ceremony after his meltdown, but the organization’s claim was called into doubt on Thursday.

Sources told The Post that Rock was never consulted about whether to bounce the “King Richard” star after the on-stage smackdown.

“No one ever asked Chris if Will should leave. They never consulted him. It was the Oscars producer Will Packer who made the final decision to let Will stay,” said one insider.

TMZ reported Thursday that Packer was the one who told Smith he could stay — despite producers and Academy officials being split on the matter.

“Packer walked up to Will and said, ‘We do not want you to leave,’” the outlet reported.

That contradicts the Academy’s claim in a letter to members on Wednesday that the actor had “refused” to leave the ceremony and instead stayed in the Dolby Theatre to pick up his Best Actor prize for “King Richard” to a standing ovation.

Meanwhile, Whoopi Goldberg, who serves on the Academy’s board of governors, defended the decision to let Smith choose whether to stay or go on Hollywood’s biggest night.

“I’m going to tell you why he got the option,” she told her cohosts on “The View” Thursday. “Picture, well, OK, they come back from break, now if he’s in some sort of state and he’s struggling and they’re trying to get him out the door and it’s still on camera.”

Rock broke his silence for the first time since the slap on Wednesday night while on tour in Boston, saying he was still “processing” the attack.

Calls to Rock’s rep were unreturned. The Post has reached out to Packer, and the Academy was unavailable for comment.