On Monday, a photo surfaced of Canadian Prime Minister Justin Trudeau wearing brown face during a party back in 2001. The photo was taken during an “Arabian Nights”-themed gala and appeared in the West Point Grey Academy's 2001 yearbook, a private day school where Trudeau was a teacher, TIME Magazine reported.

Trudeau's identity was confirmed by Zita Astravas, the media relations lead of the Liberal Party of Canada, the party Trudeau is apart of.

“It was a photo taken while he was teaching in Vancouver, at the school’s annual dinner which had a costume theme of ‘Arabian Nights.' He attended with friends and colleagues dressed as a character from Aladdin,” Astravas said.

From TIME:

TIME reached out to multiple people who attended West Point Grey’s spring gala in 2001, including three of the four women in the photo with Trudeau. Most were reluctant to talk about it. One former staff member declined to comment, citing loyalty to Trudeau. Others said they did not remember Trudeau at the party. Two people contacted by TIME acknowledged the existence of the picture, which has been the subject of gossip within the West Point Grey community. Trudeau was not the only person in costume at the 2001 gala event. Of the individuals in six photographs from the event published in the yearbook, Trudeau appears to be the only one who darkened his skin. Many who dressed up for the “Arabian Nights” gala are still at the school, including current headmaster Stephen Anthony, who is pictured wearing what appears to be a crown.

Trudeau apologized for the photo.

“I shouldn’t have done that. I should have known better and I didn’t. I’m really sorry.," he said.

“Yes it was," he said, in response to reporters asking if he thought the photo was racist. "I didn’t consider it racist at the time, but now we know better.”