Beatty wrongly declared La La Land instead of Moonlight as the winner due to a so-called technical error.
But, speaking about it for first time, Faye Dunaway is clearly blaming her Bonnie & Clyde for the massive mix-up.
"So he took the card out, and he didn't say anything," Dunaway told NBC Nightly News last night.
"He paused. He looked over me, offstage. He looked around. And I finally said, 'You're impossible'. I thought he was joking. I mean, I thought he was stalling.
"Warren's like that. He kind of holds the power and makes people... A dramatic pause. But it's part of his charm. And I read the name of the film on the card."
Dunaway added that she isn't angry about the mix-up but does admits to feeling "very guilty." She added: "Yeah, completely. And we were, I won't say deer in the headlight, but you are completely stunned. You don't know what has happened. I thought, 'I could have done something, surely. Why didn't I see Emma Stone's name on the top of the card?"