Billy Bush Rips Author Amy Griffin as 'Unhinged' After Wedding Confrontation

Billy Bush is ripping Amy Griffin for allegedly making someone else's wedding all about herself ... and he's got some pretty harsh words for the author.

The former "Access Hollywood" host detailed the drama on his "Hot Mics" podcast, claiming Amy confronted him earlier this month at Jennifer Meyer's wedding to Geoffrey Ogunlesi in Hawaii.

Billy says he spotted Amy talking to Demi Moore, who appeared to encourage her to approach him ... and things quickly got tense.

According to Billy, Amy was sweating and shaking as she confronted him over his previous coverage, questioning whether the cover art for her memoir, "The Tell," had been stolen.

Billy says Amy insisted her publisher chose the artwork before accusing him of being abusive ... and even approached his girlfriend, Ali, asking how she could date someone who was allegedly mistreating her.

But Billy wasn't having it, blasting Amy for causing a scene at another woman's wedding ... saying, "I mean, the nerve ... imagine making it all about you."

The bad blood stems from Billy's coverage of Amy's memoir, which has faced controversy over allegations that she used another woman's sexual abuse story. Amy has denied those claims.