The Oscars ceremony momentarily came to an abrupt halt during a confrontation between best actor nominee Will Smith and comedian/actor Chris Rock.

Late in the ceremony, Mr. Rock took the stage to introduce the nominees for the best documentary feature award.

Mr. Rock bantered with several audience members, including actor Mr. Smith and his wife, Jada Pinkett Smith, who wore her hair short.

Riffing on her coiffeur, Mr. Rock mentioned both stars by name and said he was excited to watch “G.I. Jane 2,” a reference to the 1997 film “G.I. Jane,” in which Demi Moore wore her hair in a crew cut. Ms. Pinkett Smith has said she has alopecia, a condition that causes hair loss.

After the joke, a visibly upset Mr. Smith, who is nominated for his work in "King Richard," ascended to the stage and appeared to strike Mr. Rock in the face. Mr. Smith then repeatedly yelled, “Keep my wife’s name out your f—ing mouth!” Some broadcasters, including YouTube TV, bleeped out the exchange; on social media unbleeped clips of the exchange that aired overseas spread like wildfire.

Mr. Rock, seemingly stunned, said, “Will Smith just slapped the shit out of me!” and tried to defend the joke to Mr. Smith from the stage, telling him, “It was a ‘G.I. Jane’ joke.”

A few minutes later, rapper and music producer P. Diddy, introducing a segment honoring the 50th anniversary of “The Godfather,” said, “Will and Chris, we're going to solve that like family at the gold party, but right now we're moving on with love."