Late night TV talk show host John Oliver grilled Hollywood star Dustin Hoffman over sexual harassment allegations, during a pre-screening panel meant to celebrate the 20-year anniversary of the film “Wag the Dog.”

Oliver, who hosts “Last Week Tonight” on HBO, was moderating a panel that included Hoffman, Robert De Niro, producer Jane Rosenthal and director Barry Levinson on stage in front of a live audience. The hour-long chat started with discussion of the film, but soon diverged into a tense series of exchanges between Oliver and Hoffman.

Several video clips of the heated exchange were recorded by an audience member and posted online by the Washington Post.

In the clips, Hoffman addresses allegations from Anna Graham Hunter, who claimed in a guest column for the Hollywood Reporter that the actor tried to grab her and used vulgar and sexually suggestive language when she was a 17-year-old intern on the set of the 1985 film “Death of a Salesman.” Her article, titled “Dustin Hoffman sexually harassed me when I was 17,” includes several transcribed journal entries (and a few photographed originals) from that time.

Hoffman’s response was published alongside Hunter’s column, and Oliver read from it during the panel: “I have the utmost respect for women and feel terrible that anything I might have done could have put her in an uncomfortable situation. I am sorry. It is not reflective of who I am.”

Responding to Oliver, Hoffman suggested that past actions don’t reflect who he is today, and many of the reports about his apology got it wrong.

“There’s a key word that’s left out… And that is IF I did anything that was out of sorts or I embarrassed her, I apologize. And the word IF was important. Now it just says ‘He apologizes.’”

Oliver shot back.

“It’s that kind of response to this stuff that pisses me off,” he said, drawing several gasps from the crowd. “It IS reflective of who you were,” he continued. “If it happened – and you’ve given no evidence to show that it didn’t happen – then there was a period of time, for a while, when you were creepier around women. So it feels like a cop-out to say, ‘Well, this isn’t me.’”

Hoffman added that he doesn’t know who Graham Hunter is, and had never met her. “If I met her it was in a concert with other people,” he said.

Hoffman accused Oliver of making a “quick judgment,” suggesting that sexual jokes among cast and crew on sets were commonplace at that time.

“One of the things was, you come to work on Monday, did you have sex Friday? You break it up,” he said. “I said a stupid thing, but I said it in the midst of the crew, and they said their stupid things, but they were sexual in terms of the humour of it, but that team – that was 40 years ago (sic).”

Oliver responded: “It feels like dismissals or re-contextualizing it is not actually addressing it,” before adding, “I get no pleasure from having this conversation, but you and I are not the victims here.”

Then, Hoffman asked Oliver why he would believe Graham Hunter’s decades-old journal entries.

“There’s no point in her lying,” Oliver replied.

“Well, there is a point in her not bringing this up for 40 years,” Hoffman said.

Oliver shook his head at that response, saying: “Oh, Dustin…”

Hoffman also addressed groping claims made by actress Katharine Ross, with whom he co-starred in the iconic film “The Graduate.” Hoffman, who had previously said he “pinched her right buttocks,” told Oliver that he touched her during an “unhappy” moment between takes on set.

“She was very upset and she turned and said, ‘Don’t you ever do that again.’ And it was, I thought, an overreaction because of what was going on all day,” he said. “She later apologized. We were very good friends on that film.”

During the panel discussion, Hoffman said that was an example of “things that we do between takes.”

Oliver said that illustrates why a “cultural shift” is necessary, because that kind of behaviour “sounds benign” when you’re the one in a position of power.

“What may seem completely fine or normal to a certain group of people can have victims at the other end of it,” Oliver said.

The late-night host said he could have left the issue unaddressed, but “that leaves me at home later at night hating myself.”