La La Land / Moonlight Best Picture mix-up: How the biggest mistake in Oscars history happened

While the majority of the 89th Academy Awards took place without a hitch, the final announcement of the evening - the coveted Best Picture award - was an unprecedented disaster.

Presenters Warren Beatty and Faye Dunaway announced La La Land as the overall winner, when - in reality - Moonlight had taken the top prize.

"I opened the envelope and it said: Emma Stone, La La Land,” Beatty explained. “That's why I took such a long pause and looked at Faye, and at you. I wasn't trying to be funny."

Conversely, Emma Stone has claimed she was holding her Best Actress announcement card, telling press backstage: “I was also holding my Best Actress in a leading role card that entire time.

“So whatever story - I don’t mean to start stuff - but whatever story that was, I had the card. So, I’m not sure what happened. And I really wanted to talk to you guys first.”

While exactly what happened remains a mystery - and Faye has declined to comment on the situation to reporters, a past interview with the two Oscars balloting co-leaders - the only two people who know the final Oscars results - is very revealing.

“The producers decide what the order of the awards will be,” Brian Cullinan told Medium. “We each have a full set. I have all 24 envelopes in my briefcase; Martha [Ruiz] has all 24 in hers.

“We stand on opposite sides of the stage, right off-screen, for the entire evening, and we each hand the respective envelope to the presenter. It doesn’t sound very complicated, but you have to make sure you’re giving the presenter the right envelope.”

Just three days ago, Cullinan also gave an interview with the Huffington Post in which he revealed what would happen "if" a mix-up happened on the night.

“We would make sure that the correct person was known very quickly," he told the publication. "Whether that entails stopping the show, us walking onstage, us signaling to the stage manager — that’s really a game-time decision, if something like that were to happen. Again, it’s so unlikely."

So unlikely, yet it did happen. Los Angeles Times writer Jeffrey Fleishman reportedly claimed that, mid-way through La La Land's acceptance speech, someone shouted from the stage side " "Oh, f-ck. Oh my God. He got the wrong envelope."

The consensus is therefore that the wrong envelope was opened by Beatty while Stone held the other, therefore meaning both their stories check out.

An official statement has since been delivered, clarifying that the company entrusted to manage the winning envelopes was at fault.

“The presenters had mistakenly been given the wrong category envelope and when discovered, was immediately corrected," PricewaterhouseCoopers said. "We are currently investigating how this could have happened, and deeply regret that this occurred. We appreciate the grace with which the nominees, the Academy, ABC, and Jimmy Kimmel handled the situation."

Meanwhile, Moonlight director Barry Jenkins and Best Supporting actor Mahershala Alit have both commented on the event. Read the full list of winners here.