"I'm disappointed in myself, I'm pissed off at myself for having done it".
In response to the photo, Zita Astravas, the media relations spokesperson from Trudeau's Liberal Party of Canada, confirmed the prime minister was pictured in the image and claimed that he was dressing up as a character from Disney's Aladdin.
The photo shows a 29-year-old Trudeau, the son of former Prime Minister Pierre Trudeau, wearing a white turban and white Arab-style robes while covered in the makeup. He said he had made a number of calls to "friends and colleagues" and will have many more to make. Others at the event seen in different costumes in different photographs did not appear to have darkened their skin with makeup, Time reported.
Virginia governor Ralph Northam admitted he had worn blackface while dressing up as Michael Jackson.
Political analysts noted that for Mr Trudeau, a prime minister of the Instagram age, who had meticulously constructed a global image as a progressive on issues such as gender equality, Indigenous and minority rights, the image of him in brownface could be politically damaging.
The prime minister's office did not return a request for comment, nor did the Liberal Party of Canada.
Trudeau noted another time he wore blackface, saying: "When I was in high school I dressed up at a talent show and sang "Day O" with makeup on". He marked the International Day for the Elimination of Racial Discrimination previous year with a statement about not becoming "complacent" in the fight against racial discrimination.
Even though the man did not attend the party, he said that he came across the photo in July and thought it should be made public.
This is a breaking news story and will be updated.
"It was something that I didn't think was racist at the time but now I recognize that it was something racist to do and I am deeply sorry", Trudeau said. "I should have known better", he said, adding, "I didn't consider it a racist action at the time".
The photo's publication could spell more trouble for Trudeau, who polls say is facing a serious challenge from Conservative leader Andrew Scheer.
"The wearing of blackface/brownface is reprehensible, and harkens back to a history of racism and an Orientalist mythology, which is unacceptable", Farooq said in a statement.