Trudeau was standing with French President Emmanuel Macron, U.K. Prime Minister Boris Johnson and Dutch Prime Minister Mark Rutte at a Buckingham Palace reception during the first night of the 2019 North Atlantic Treaty Organization (NATO) Summit in London when he made the remarks.
"Is that why you were late?" Johnson can be heard asking.
"He was late because he takes a 40-minute press conference," Trudeau replied.
Trump took questions from the press earlier Tuesday in which he announced the G7 Summit in 2020 would be held at the Camp David presidential retreat center.
"You just watched his team's jaws drop to the floor," Trudeau added later in response to inaudible comments from Macron.
In a press availability Wednesday, Trump responded to the video by saying Trudeau was "not very happy" about Trump pushing Canada to contribute more to NATO.
"He's two-faced," Trump said, adding that he is a "very nice guy."
Trudeau sought to do damage control Wednesday, saying "the relationship between Canada and the United States is deep and goes far beyond the relationship between prime minister and the president."
"Although I will say as you all know, a very good and constructive relationship between me and the president ... has allowed us to move forward on protecting our workers through the NAFTA deal, the steel tariffs got lifted, to many initiatives around the world," Trudeau said.
The video has since made its rounds on social media, gaining the attention of various big-name Twitter users. New York Times reporter Maggie Haberman, for example, tweeted, "Can't get over this video, both for the fact that POTUS hates the thought of anyone laughing at him and for the fact that he long used 'other countries are laughing at us' as an attack against his predecessors."
Former Canada Prime Minister Stephen Harper's spokesman Andrew MacDougall responded to the clip saying Trudeau should know better.
"By this point in his tenure the Prime Minister should [realize] that events with pool cameras need to be approached and managed as on the record events,” MacDougall tweeted. "Hopefully this gaffe doesn’t wind the President up at a sensitive time for NAFTA and the Meng/Huawei file."
English broadcaster Piers Morgan said the president would love the fact that "they're all talking about him."
New York Magazine contributor Yashar Ali, along with other news outlets, pointed out a fifth person who appears to be Princess Anne, daughter of Queen Elizabeth II.
"That looks like the Princess Royal next to Trudeau...her hairstyle for sure. A senior member of the Royal Family in the mix...wow," he wrote on Twitter.
Trump and Macron clashed during their joint press conferences at the summit Tuesday. The president first reacted to Macron's early November interview with The Economist in which he said the United States' actions in Syria are contributing to the "brain death" of NATO. Trump called Macron's comments "very, very nasty" and "insulting."
He later asked Macron if he wanted to take back "some nice ISIS fighters" that the U.S. has captured, some of which Trump said came from France. Macron responded by saying many are coming from Syria, Iraq and other Middle Eastern countries.