(CNN) -- Director Barry Jenkins said he was "speechless" after his movie "Moonlight" was announced as the winner of best picture on Sunday night, following an unprecedented moment in Oscars history. And he wasn't the only one.

"Is that the craziest Oscar moment of all time?" Emma Stone asked backstage. "We made history tonight."

But what exactly happened that led to that now-infamous moment where "La La Land" was mistakenly announced as best picture at the Academy Awards?

Here's how it all went down:

Faye Dunaway and Warren Beatty present

Faye Dunaway and Warren Beatty -- on hand to celebrate the 50th anniversary of "Bonnie and Clyde" -- presented the nominees for best picture. On stage, Beatty was given the task of opening the envelop that was supposed to contain the winner. (Later, Beatty would say it contained the name of a winner, but not the winner.)

On stage, Beatty looked at the card and said, "And the Academy Award..."

The crowd laughed, assuming he was building suspense.

He looked down at the card again and then looked at Dunaway.

"...for best picture..."

Dunaway playfully told Beatty, "You're impossible." She assumed he was joking around.

"Come on," she prompted him.

He showed her the card, and Dunaway read it aloud.

"'La La Land,'" she said.

'La La Land' has a lovely night...briefly

"La La Land" producer Jordan Horowitz was the first to speak. Producer Marc Platt followed.

As Platt spoke, viewers at home saw someone run across the stage behind him.

From the crowd, "Moonlight" actor Mahershala Ali, a winner for best supporting actor, noticed the activity.

"When I did see security or people coming out on stage, and their moment was being disrupted in some way, I got really worried," he told press backstage.

Jenkins wasn't surprised by the initial result.

"I think all the movies that were nominated were worthy so I took the result," he said backstage. "I applauded like everyone else."

On stage, "La La Land" producers were approached by a man wearing a headset and holding an envelope.

Platt called producer Fred Berger to the mic next. As Berger began speaking, Beatty started heading to the mic, but Berger beat him to the announcement.

"We lost, by the way, but, you know," he said.

Horowitz clarified: "I'm sorry, there's a mistake. 'Moonlight,' you guys won best picture."

"This is not a joke," he said, gesturing to the "Moonlight" cast and producers and inviting them to stage.

Platt added: "This is not a joke. They read the wrong thing."

Horowitz showed the envelope to the crowd.

"I wanted to express to them that they had won," he told CNN later.

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