LOS ANGELES - An accountant for theAcademy Awards botched the meticulous procedure for announcingthe Oscar for best picture when he handed victory to "La LaLand" before declaring "Moonlight" the real winner,PricewaterhouseCoopers (PwC) said on Monday.

Accountant Brian Cullinan, who media reports said had beentweeting backstage shortly before, gave presenters Warren Beattyand Faye Dunaway the wrong envelope for the movie industry's topaward on Sunday, the accounting firm said in a statement.

In a gaffe that stunned the Dolby Theatre crowd in Hollywoodand a television audience worldwide, "Cullinan mistakenly handed the back-up envelope for Actress in a Leading Role instead ofthe envelope for Best Picture" to Beatty and Dunaway, PwC said.

"Once the error occurred, protocols for correcting it werenot followed through quickly enough by Mr. Cullinan or hispartner."

The Wall Street Journal and celebrity website TMZ.comreported that Cullinan had posted a backstage photo of actressEmma Stone on social network Twitter minutes before the mix-up.

The photo, from Cullinan's Twitter account, was laterdeleted but was still viewable on Monday on a cached archive ofthe page. Cullinan could not immediately be reached for comment.

The mistake was not rectified until the "La La Land" castand producers were on stage giving their acceptance speeches. Itwas left to the musical's producer, Jordan Horowitz, to putthings right.

"Guys, guys, I'm sorry. No. There's a mistake," Horowitzsaid. "'Moonlight,' you guys won best picture. This is not ajoke."

It took three hours for PricewaterhouseCoopers, which hasbeen overseeing Academy Awards balloting for 83 years, initiallyto confirm that Beatty and Dunaway received the wrong categoryenvelope.

PwC said it took full responsibility and apologized to thecasts and crews of "La La Land" and "Moonlight."

"We sincerely apologize to Warren Beatty, Faye Dunaway,(host) Jimmy Kimmel, (broadcaster) ABC, and the Academy, none ofwhom was at fault for last night's errors," it said in itsstatement.

The Academy of Motion Picture Arts and Sciences, whichorganizes the Oscars, also apologized for the mishap and said itwas committed to upholding the integrity of the Oscars.

"We have spent last night and today investigating thecircumstances, and will determine what actions are appropriategoing forward," it said in a statement.

An embarrassed Beatty carried the envelope to the glitzyGovernor's Ball after the show, with the writing clearly saying"actress in a leading role." "La La Land" star Stone had beenawarded that Oscar moments before.

"Except for the end, it was fun," Kimmel said on Monday,referring to the Oscar show he hosted.

"You know it’s a strange night when the word ‘envelope’ istrending on Twitter," he said on his ABC show "Jimmy KimmelLive."