Moments before winning the Oscar for Best Actor, Will Smith shocked audiences by hitting host Chris Rock on stage.
Smith struck Rock only seconds after he made a joke about his wife Jada Pinkett Smith, before returning to his seat and yelling at Rock.
Will shouted, "Keep my wife's name out of your f***ing mouth" as the audience gasped.
It seemed clear that many in the audience thought the hit was part of a comedy skit between the two, as the audience awkwardly laughed when a stunned Rock said: "Will Smith just slapped the s**t out of me."
The violent outburst was condemned by The Academy, which said: "The Academy does not condone violence of any form.
"Tonight we are delighted to celebrate our 94th Academy awards winners, who deserve this moment of recognition from their peers and movie lovers around the world."
The watching audience and people on social media were shocked Will had resorted to violence to try and settle a dispute.
A tearful Smith later apologised, and revelations from his past may reveal why he felt the need to act in the way he did.
What caused Will Smith to hit Chirs Rock?
Revelations about domestic violence in Will Smith's upbringing have led to theories that he hit Chris Rock out of a need to fend for his family.
The response seemed out of proportion to some and has been widely condemned on social media, though others have praised Will for his actions.
As a child, Will previously revealed his father was violent towards him, his mother and his siblings.
In his autobiography, Will wrote: "When I was nine years old, I watched my father punch my mother in the side of the head so hard that she collapsed... I saw her spit blood. That moment in that bedroom, probably more than any other moment in my life, has defined who I am."
Will claimed that his career since the horror incident has been a "string of apologies" for not acting to protect his mother at the time, despite being only nine.
"What you have come to understand as ‘Will Smith,’ the alien-annihilating MC, the bigger-than-life movie star, is largely a construction – a carefully crafted and honed character designed to protect myself. To hide myself from the world. To hide the coward," he added.
It isn't the first time Rock has taken a swipe at Will. In 2016, the comedian commented on Jada's boycotting of the event.
He quipped: "Jada got mad, said she’s not coming. Jada boycotting the Oscars is like me boycotting Rihanna ’s panties. I wasn’t invited!"
Why did Will Smith hit Chris Rock?
Will Smith clearly took offence at a joke made by Chris Rock about Jada's alopecia.
Jada has suffered from the hair loss condition and appeared to not take too kindly to Rock's joke about her.
Rock said: "Jada, love you, G.I. Jane 2, can’t wait to see it."
The joke was a reference made to the 1997 film G.I. Jane, which starred a bald Demi Moore as the lead.
Will initially seemed to laugh at the joke, before being seen moments later on stage advancing on Rock and striking him across the face.
Accepting his Best Actor award, Will said: "I know to do what we do you’ve got to be able to take abuse and have people talk crazy about you and have people disrespecting you, and you've got to smile and pretend it’s OK.
"Love will make you do crazy things."
