Last year's mistake happened when a PwC partner mistakenly handed an envelope for the best actress victor category, which went to Emma Stone in "La La Land", to the presenters of the best picture category, Warren Beatty and Faye Dunaway.
Instead they ended up giving the award to La La Land because they had the envelope for Best Actress, which went to Emma Stone for her role in the romantic musical.
You may remember the famous moment at the Oscars a year ago, when the wrong film was announced as the victor of the biggest prize of the night.
The people involved in handing over the results envelopes are forbidden from using their mobile phones or social media during the show.
- All three balloting partners will attend show rehearsals and practice what to do if something goes wrong. They will sit with Oscar producers in the show's control room, and will have a complete set of all of the winners' envelopes, AND they will know all of the winners by memory.
The three partners will practice what to do if something goes wrong, so the mistake can be rectified quicker than past year.More news: The number one rum, Bacardi, to buy the number one Tequila, Patrón
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Both the celebrity presenter and the stage manager will have to confirm to the partners that they have the correct envelope before stepping on stage. The Moonlight team finally got their moment in the limelight.
After the wrong victor was named at the Academy Awards in 2017, strict new rules have come into place to ensure that the mix-up won't happen again.
He will be personally involved in the operations this year. The accounting firm PricewaterhouseCoopers admitted 2017's big "oops" was because an employee handed off the wrong envelope.
Although questions were raised over PwC's future at the Oscars, the organisation kept its contract because the mistake was down to a "very public human error".
The Motion Picture Academy is confident "envelopegate" will never happen again at the Oscars.