London (CNN) After President Donald Trump called him "two-faced," Canada's Prime Minister, Justin Trudeau, admitted Wednesday that he and other world leaders were talking about the US President when they were caught on camera at a Buckingham Palace event the night before.

"Last night I made reference to the fact that there was an unscheduled press conference before my meeting with President Trump. I was happy to be part of it but it was certainly notable," Trudeau said during a Wednesday press conference.

Trudeau indicated that he wasn't concerned about his comments impacting the US-Canadian relationship, but Trump reacted angrily earlier Wednesday calling Trudeau "two-faced," before adding, "honestly with Trudeau, he's a nice guy."

Trump also canceled his own press conference scheduled for the end of his trip to the NATO summit. The President was caught on a hot mic of his own after the cancellation, saying, "Oh, and then you know what they'll say. 'He didn't do a press conference. He didn't do a press conference.' That was funny when I said the guy's two-faced, you know that."

The 25-second clip was first reported by CBC , begins with Johnson asking Macron why he was late.

"Is that why you were late?" Johnson asked.

Macron nodded, as Trudeau replied, "He was late because he takes a ... 40-minute press conference at the top."

At no time in the video do the leaders mention Trump by name.

None of them seemed to be aware that the conversation was being recorded, although they were talking openly and loudly enough to be heard by others.

"You just watched his team's jaws drop to the floor," Trudeau also appears to say at one point. Trudeau said during his press conference that the comment was made in reference to Trump's announcement during their bilateral meeting that the upcoming G7 summit will be hosted at Camp David.

A top official working with one of the world leaders caught up in Trudeau's hot mic moment said Trump's unpredictability has become par for the course at NATO gatherings.

"There's an unpredictability that we've come to expect. But that is how we deal with it," the official said. "I think everybody would describe it as that -- unpredictability ... It's not new."

"Every different leader has teams who now and then (had) jaws drop at unscheduled surprises, like that video for itself, for example," Trudeau said.

Johnson at a press conference said it was "nonsense" to suggest the video indicated he didn't take Trump seriously.

"I don't know where that's come from," he added.

Microphones could only pick up snippets of the conversation at the reception, which the press was given limited access to.

Trump also criticized Trudeau over the fact Canada does not currently meet NATO's 2% defense spending target.

"The truth is I called him out on the fact that he's not paying 2% and I guess he's not very happy about it," Trump said, adding that "he should be paying 2%" and that Canada "has money."

"I can imagine he's not that happy, but that's the way it is," Trump said.

Trump is "annoyed" and "bothered" by the hot mic video but believes that the two leaders will likely work through it, according to a source who has recently spoken to the President. The source said the video was not why Trump canceled his news conference.

Trump and Trudeau had a brief exchange WEdnesday morning, but the Canadian Prime Minister did not apologize, according to a NATO member source. Separately, a Canadian official said Trudeau had given Trump "context" about the incident captured on video.

A spokeswoman for Macron at the Elysée Palace told CNN they had "no comment. This video does not say anything special." A spokesperson for Rutte also told CNN they do not comment on closed-door sessions.

Clash with Macron

Trump spent Tuesday in meetings in London headlined by a clash with a key ally, France. He met with NATO Secretary General Jens Stoltenberg, Macron and Trudeau, making extended remarks and taking questions from the press on each occasion.

Trump's one-on-one meeting with Macron was remarkably tense as the French President refused to back down from remarks that Trump called "nasty" and "insulting." Last month, Macron had described NATO as suffering from "brain death" caused by American indifference to the long-time alliance.

But the two leaders appeared to be on good terms as they walked onto the road leading to 10 Downing Street together for another reception following the gathering at the palace. It appeared that Trump had given Macron a lift in his motorcade vehicle commonly referred to as "the beast."