Chris Rock made a joke about Jada Pinkett Smith's shaved head not looking good with her husband, Will Smith.
Presenting the award for Best Documentary, Rock joked, "More I love you, 'G.I. Gen 2,' can't wait to see it."
The camera cut to Pinkett Smith, who rolled her eyes as she sat next to Smith.
"It was a good one," said The Rock, responding to the joke not playing out properly.
Pinkett Smith has been open about her struggle with alopecia, an autoimmune disorder that leads to hair loss
Rock then said, "Uh uh," and laughed as Smith walked up to him on stage and slapped Rock in the face.
According to CNN reporter Stephanie Allum, those in the audience heard The Rock take a hit. Smith said twice during the incident, according to the alum, "Keep my wife's name out of your mouth!"
The theater went silent and Rock said, "It was the greatest night in the history of television."
According to the LAPD, Rock declined to press charges.
CNN has reached out to Smith's publicist for comment.
Sean "Diddy" Combs later went on stage and told Smith and The Rock that they would settle things "like family" later.
About 40 minutes after the incident, Smith returned to the stage to accept the Oscar for Best Actor and apologized to the Academy and his fellow nominees for the incident, but did not name Rock.
He accepted the award tearfully for his role as Richard Williams, father of Venus and Serena Williams, in the film "King Richard". Smith said Williams was "a staunch defender of his family."
Smith said, "I know what we do, you have to be able to abuse and get people to talk about you. In this business, you have to make people disrespect you. And you have to smile." And pretend it's okay."
Smith also talked about being a "savior" and thanked the tennis legend and his family.
Smith shared that prior to his victory, fellow nominee Denzel Washington shared some wisdom with him: "Be careful in your highest moment, that's when the devil comes for you."
Smith concluded by saying that he hoped the Academy would welcome him back.