Dubbed #MeTrudeau by the tabloids, the alleged incident has only now resurfaced after the original story, which was published in a local paper in 2000, was retweeted last weekend.
A few days after the music festival happened in Creston, B.C, an editorial story in the 'Creston Valley Advance' newspaper claimed that he had groped a young female reporter.
The unsigned editorial does not say exactly what was supposed to have taken place, but it also made it very clear that the female reporter felt "blatantly disrespected".
The Canadian PM had been involved in organising the music festival to raise money for an avalanche safety charity.
He was inspired to get involved after his younger brother Michel Charles-Émile Trudeau tragically died in an avalanche in 1998, while skiing in Kokanee Glacier Provincial Park. He was 23 at the time of his death.
The editorial reads: "It’s not a rare incident to have a young reporter, especially a female working for a small community newspaper, be considered an underling to their ‘more predominant’ associates and blatantly disrespected because of it.
"But shouldn’t the son of a former prime minister be aware of the rights and wrongs that go along with public socializing?
"Didn’t he learn through his vast experiences in public life, that groping a strange young woman isn’t in the handbook of proper etiquette regardless of who she is, what her business is, or where they are."
The editorial also claims that Trudeau apologized at the time, telling the reporter: "I'm sorry. If I had known you were reporting for a national paper, I never would have been so forward."
But the Canadian PM now says he has no recollection of the incident. "I remember that day in Creston well…I had a good day that day. I don’t remember any negative interactions that day at all," he said last night.

Um, what? #cdnpoli #loc #MeToo pic.twitter.com/6P7iiPQRZA

— Warren Kinsella (@kinsellawarren) June 6, 2018

Speaking on CBC News, the paper's former publisher Valerie Bourne said she remembered the reporter being distressed at the time.

"My recollections of the conversation were that she came to me because she was unsettled by it. She didn't like what had happened. She wasn't sure how she should proceed with it because of course we're talking somebody who was known to the Canadian community," Bourne said.
"It was a brief touch. I would not classify it or qualify it as sexual assault."
Brian Bell edited the newspaper at the time and says that he "certainly believe that it happened".
"This reporter was of a high character in my opinion," he continued, "and was professional in the way she conducted herself and there's no question in my mind that what was alluded to, written about in that editorial, did happen."

PM Justin Trudeau addresses groping allegation, says he doesn’t recall 'negative interactions.' https://t.co/wRDTqSeufY #cdnpoli pic.twitter.com/29Yg8s5DD9

— Toronto Sun (@TheTorontoSun) July 2, 2018