Most awkward Oscars moment ever?

In surely the worst blunder in Oscar history, the Academy Award for best picture was handed to the wrong nominee this evening - and the mistake was only discovered halfway through the acceptance speeches.

Faye Dunaway announced the wrong winner for best picture at the end of the night, awarding the trophy to La La Land when it actually was supposed to go to Moonlight.

Moonlight director Barry Jenkins said he was "speechless" when the correct result was offered.

It all started as Dunaway's co-presenter, Warren Beatty, opened the envelope to read the winner for best picture. He looked confused, took a long pause, and then looked over at Dunaway, who clearly thought he was doing some sort of bit.

"You're awful!" she said, as the crowd laughed nervously. "God."

Beatty then handed the envelope to Dunaway, who announced "La La Land!"

The cast and crew of La La Land arrived on stage to accept the award before someone realised the mix-up, which set off moments of extreme confusion, slight panic and...well, no one really knew what was happening.

"There's been a mistake," producer Jordan Horowitz said, as he ran onstage. "Moonlight, you guys won."

As Beatty later explained to the crowd, he had paused to look at the envelope, which read "Emma Stone, La La Land." Stone had just won best actress.

"That's why I took such a long look at Faye...I wasn't trying to be funny," Beatty explained to the audience. "This is Moonlight the best picture."

La La Land's cast and crew were halfway through their acceptance speeches when the mistake was realised.

Host Jimmy Kimmel joked: "Warren, what did you do?"

The Washington Post described it as the most shocking Oscars moment ever and the error was quickly picked up as a topic of discussion by viewers.

Afterwards, Emma Stone spoke to reporters backstage:

"Of course it was an amazing thing to hear La La Land. We would have loved to have won best picture. But we are so excited for Moonlight. I think it's one of the best films of all time.

"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 that card."

NOTE: It has since emerged that there are back up envelopes for every category and Beatty was given the Emma Stone back up envelope by mistake. Off stage, they realised that they still had two best picture envelopes. The best picture envelope for Moonlight hadn't yet been opened. Executives from Price Waterhouse who tally the Oscar results immediately realised there was a problem when Dunaway read out the name La La Land. An official tried to get on stage to immediately rectify the mistake.