Sacha Baron Cohen was on the run from Secret Service agents when an interview with Ben Carson went hysterically awry.

Human chameleon Cohen managed to land an interview with the secretary of housing and urban development, he’s revealed. Cohen was planning to conduct the chat as his wild character “OMGWhizzBoyOMG” — a Finnish YouTuber obsessed with unboxing Shopkins kids collectibles.

But the plan fell apart just before the interview began at the Washington, DC, Mandarin Oriental.

“We get there and there were Secret Service everywhere … it turns out that there’s a conference there … and there were Secret Service throughout the building. So I was like, ‘S–t! How do I get him?’” Cohen told a group of SAG members at a private talk, we hear. Sarah Silverman had urged Cohen to recall the wild Carson tale at the event.

Worried about being ID’d by the agents, Cohen recounted, “I spoke to my lawyer and I said, ‘What happens if [Secret Service] wants to see my ID?’ And he goes, ‘Well, you have to show him your ID then, that’s illegal not to show him.’ ”

Cohen additionally had a fake ID on him, but his lawyer cautioned that if he presented it, he could be arrested. “I go, ‘OK what if I bend over and the fake ID falls on the floor? And they pick it up?’” Cohen asked the legal eagle. “And he goes, ‘That might be OK.’ ” Entering the hotel, “the Secret Service are there I bend over … they pick it up, fine, I walk on,” Cohen recalled.

But once he reached the interview room to meet Carson, the in-disguise star saw “a press officer of the White House there. And he sees all these Shopkins that I’ve got there. And he goes, ‘What are those?’ And I go [in character], ‘Those are Shopkins!’ He said, ‘I know what they are — why are there Shopkins here?’ ”

When Cohen again answered in character as the punk-haired, bespectacled, Finnish toy obsessive, the White House staffer “literally gave one look to the Secret Service, and Ben Carson’s leg is coming in and literally falls backwards.”

With Carson abruptly pulled, “Then they looked — the rest of the Secret Service — like something is going on.”

Cohen hurried to another room the show had booked — but, “I hide in this other room. Then I find out the Secret Service is coming to our room. I booked another room upstairs. I go to the other room.”

That’s when Cohen’s security adviser informed the gadfly comic, he recalled, “The Secret Service know you’re here, and that something’s up, they don’t know what it is, whether it’s an attack or something’s going on, and they’re looking for you.”

Cohen also learned that “some of the Secret Service were dressed as housekeepers and room service guys — we actually have behind-the-scene footage of Secret Service workers coming and listening through the door.”

Luckily Cohen also planned “an escape route … down around the back of the building through the garbage. And the security guard said … ‘They’re by the garbage.’ And I said, ‘How do we get out of the building?’ There’s, like, 18 of these guys.”

According to Cohen, his guard told him, “’We’re going to position a getaway car in front of the hotel … You’ve got 25 feet from the elevator opening to the car.’ And I go, ‘What about the Secret Service guys?’ And he goes, ‘If they come towards you, I’m gonna take them down.’ I go, ‘What?!’ He goes, ‘Because that’s what I have to do to get you into the car.’ ”

In the end, Cohen said, “I manage to get to the car, and we were followed by a police car for about five minutes and they didn’t pull us over so I managed to get away with that.”

Cohen was nominated for a Golden Globe for the series and is now being hotly tipped as a potential Emmy nominee.

Beltway insiders who did appear on the show included Dick Cheney, Howard Dean, Barney Frank, Corey Lewandowski, Trent Lott, Bernie Sanders and veteran newsman Ted Koppel.

Cohen has previously said he’d booked Carson for the ill-fated interview in a Q&A but has never revealed that he was afraid of being pursued by the Secret Service in the aftermath.

Carson, meantime, was just in a bizarre exchange at a Capitol Hill hearing where he misheard a California congresswoman asking about “REOs” — a real estate term — as Oreos, as in the cookies.