The man in charge of the Oscars ceremony says he thought the moment Will Smith slapped Chris Rock was a comedy set-up and didn’t realise a blow had actually been thrown until after the comedian left the stage.

Speaking publicly for the first time since the event, producer Will Packer told Good Morning America: “I thought this was part of something that Chris and Will were doing on their own. I thought it was a bit like everybody else. I wasn’t concerned at all [as Smith approached the stage].

“I figured, OK, you know, he’s going to say something or come at him, something funny is going to happen because that’s the nature of Chris and that’s the nature of Will. So, let’s see what happens.”

The moments before the slap

Describing the moments before chaos descended on the Oscars, Packer says he was watching the TV monitors as Rock took to the stage to present the best documentary award and said to his colleagues: “‘Watch this. He’s going to kill,’ because I knew he had an amazing line-up of jokes.

“We had them in the teleprompter. And ultimately, he did not get to one joke. We didn’t tell one of the planned jokes. He was just immediately freestyling. But I tell you, if there’s anybody that you don’t worry about going out in front of a live audience and riffing off the cuff, it’s Chris Rock. Nobody’s better.”

It was an unscripted joke, in which Rock compared Smith’s wife, Jada Pinkett Smith, to Demi Moore’s character GI Jane in the 1997 film – a role for which the actress shaved her head.

It’s not clear whether Rock knew that Pinkett Smith has alopecia, a condition that causes hair loss.

Read more: Alopecia charity offers alternative Will Smith speech

When the problem become clear

Packer said it was when Smith sat back down and began shouting obscenities at the stage that he realised there was a problem.

“Once I saw Will yelling at the stage with such vitriol, my heart dropped, and I just remember thinking ‘Oh no, not like this’,” he said.

While he could see it was “a confrontational moment”, he said: “I still wasn’t sure if he had struck him.”

Chris Rock ‘still in shock’ after leaving stage

Packer said he spoke to Rock when he left the stage with Oscar winners Summer Of Soul, and it was then that he understood the comedian had really been hit.

Packer described Rock as “still in shock” when he left the stage, but says he made light of the situation, joking: “I just took a punch from Muhammad Ali.”

Smith played the legendary boxer in the 2001 film Ali, for which he was also nominated for the best actor Oscar. Pinkett Smith was also in the film.

The producer said the violence left him “devastated”.

He went on to call Rock a “hero” for managing the situation so professionally.

Police were ready to arrest Smith

During the interview, Packer also said the reason that Smith was not arrested on the spot was because Rock “did not want to make a bad situation worse”.

The Academy initially said that Smith had been asked to leave the ceremony, but had refused.

Packer said it was “absolute fact” that the LAPD, who attended the incident, were ready to arrest Smith on the night, ahead of the best actor award being announced.

Smith went on to win the category for his role in King Richard.

Packer said officers came into his office and laid the situation out very clearly, saying: “This is battery. We can arrest [Smith] now.”

However, he said Rock was dismissive of the options: “Shayla [Cowan, co-producer] told me that they were about to physically remove Will Smith and I had not been a part of those conversations.

“So, I immediately went to the Academy leadership that was on site and I said, ‘Chris Rock doesn’t want that’.

“I said, ‘Rock has made it clear that he does not want to make a bad situation worse’. That was Chris’ energy. His tone was not retaliatory. His tone was not angry.

“So, I was advocating what Rock wanted at that time, which was not to physically remove Will Smith at that time. Because, as it had now been explained to me, that was the only option at that point.

“It has been explained to me that there was a conversation that I was not a part of, to ask him to voluntarily leave.”

Smith ’embarrassed’ by incident

Packer said he didn’t speak to Smith on the night, but the star phoned him the next morning to apologise.

Packer said: “He said, ‘This should have been a gigantic moment for you’ and he expressed his embarrassment and that was the extent of it.”

Smith also apologised to Rock the following day via social media.

It’s been reported that Smith also apologised to Academy executives via a Zoom call.

A formal Academy review to discuss the incident will take place on 18 April.

The LAPD say no charges have been filed against Smith.