"Nobody knew where it was." Hero producer explains "surreal" Oscars moment.

“This is not a joke,” La La Land producer Jordan Horowitz told the stunned audience at last night’s Academy Awards. “Moonlight, you’ve won best picture.”

It was the final award of the 89th annual Oscars, and the award’s presenters Warren Beatty and Faye Dunaway had just named La La Land winner. The film’s cast and crew had hopped on stage, acceptance speeches had begun…

Until wait, there’s been a mistake. Horowitz grabbed the microphone, showed the audience the correct award, and named Moonlight as best picture instead.

Now, in an interview with The Hollywood Reporter, Horowitz has explained how it went down.

“Guys in headsets starting buzzing around. They took the envelope I had. It said ‘Emma Stone, La La Land‘ on it,” Horowitz said.

“It was clear there was something wrong. They started looking for the best picture envelope. Nobody knew where it was. Then it appeared. They opened it next to me and it said ‘Moonlight.’ And so I grabbed it. I had to fix the situation.”

WATCH: ‘La La Land’ announced as #Oscars Best Picture winner, but only until a mistake is realized with ‘Moonlight’ being the real winner. pic.twitter.com/wYsUngcdwe

— ABC News (@ABC) February 27, 2017

And fix the situation, he did.

“I’m going to be really thrilled to hand this to my friends from Moonlight,” he told the stunned crowd. Moonlight tells the story of Chiron, a young black man growing up in Miami.

He has been named a “truth teller”. He’s been praised for his grace under extraordinary pressure. And, from the way he took charge and remained unflappably in control of his emotions, he’s proved himself as the guy you’d want around in a crisis.

Not to be overlooked — @jehorowitz just handled a complete train wreck with dignity and grace on the biggest stage in the world.

— Seth Grahame-Smith (@sethgs) February 27, 2017

Tell you this though: @jehorowitz wins for leadership & class.

— Jeffrey Wright (@jfreewright) February 27, 2017

That @jehorowitz handled that with class, grace, and genuine happiness for the winner is why he is at the pinnacle of the game.

— Justin Marks (@Justin_Marks_) February 27, 2017

Fellow La La Land producer, Fred Berger, was one of the first on stage to discover their movie was not the winner, and all he could manage was a small “we lost by the way,” before fading back into the crowd… Understandable, when you’re dealing with arguably the biggest annual award in cinema.

Horowitz has remained gracious in the aftermath – and the news storm – following the event.

“Look, we won six Oscars. The picture’s been a critical success, a financial success,” he told The Hollywood Reporter. “It’s been a wild ride and it ended in spectacular fashion.”

— Jordan Horowitz (@jehorowitz) February 27, 2017