Canadian Prime Minister Justin Trudeau has apologized and said he is 'p***ed off' at himself after a photo emerged showing him wearing brownface at a party 18 years ago when he was a private school teacher.

The photo, published by TIME magazine on Wednesday, shows Trudeau wearing brown makeup on his face, neck and hands while wearing a turban and robe at a party in 2001.

Trudeau admitted to wearing the racist costume when he attended an 'Arabian Nights' themed gala at West Point Grey Academy - the private school in Vancouver where he was teaching at the time.

The photo first appeared in the West Point Grey Academy 2001 yearbook.

In a press conference held on his campaign plane on Wednesday night, Trudeau acknowledged that the photo was racist and said he should have known better.

'I'm p***ed off at myself, I'm disappointed in myself,' he said.

The emergence of the photo comes just one week after Trudeau launched his campaign and could undermine his chances for re-election with less than five weeks to go before Canada's election.

A yearbook photo emerged on Wednesday showing Canada's Prime Minister Justin Trudeau wearing brownface to a party 18 years ago when he was a private school teacher in Vancouver

Trudeau admitted to wearing the racist costume when he attended an 'Arabian Nights' themed gala at West Point Grey Academy - the private school in Vancouver where he was teaching at the time. He is pictured at a press conference on board his campaign plane

Trudeau said the photo was taken at an end of year gala where the theme was Arabian nights and he dressed up in an Aladdin costume.

'I should have known better then but I didn't, and I am deeply sorry for it,' he said.

'I shouldn't have done that. I take responsibility for it. It was a dumb thing to do.'

He also admitted to wearing black makeup in high school to perform a version of African-American singer Harry Belafonte's song 'Banana Boat Song (Day-O)' during a talent show.

'These are the situations I regret deeply,' he said.

Trudeau said it was a racist act but he didn't realize it at the time and that he knows better now.

'I shouldn't have done that. I should have known better, but I didn't, and I'm really sorry. It was a dumb thing to do Justin Trudeau

He acknowledged that he had 'always been more enthusiastic about costumes than is sometimes appropriate'.

He asked Canadians to forgive him and said he would continue to fight intolerance and discrimination.

Trudeau repeatedly said he would take responsibility for his past mistakes but refused to say why he hadn't spoken about the existence of the racist photo sooner.

The Liberal Party of Canada had earlier confirmed that Trudeau, who is the leader of their political party, was in the photo.

'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',' the party's media relations lead said.

'He attended with friends and colleagues dressed as a character from Aladdin.'

He worked at the private school before entering politics and at the same time his father Pierre Trudeau was Canada's Prime Minister.

Trudeau taught French, among other classes, when he was a teacher at the private school where tuition is about $23,000 a year.

He left his teaching position there after spring in 2001.

The Liberal Party of Canada confirmed on Wednesday that Trudeau, who is the leader of their political party, was in the photo. He is pictured above on Wednesday during an election campaign event in Moncton, New Brunswick

Exclusive: Justin Trudeau wore brownface at 2001 ‘Arabian Nights’ party while he taught at a private school, Canada's Liberal Party admits https://t.co/j3UobfYNIF — TIME (@TIME) September 18, 2019

Trudeau acknowledged that he had 'always been more enthusiastic about costumes than is sometimes appropriate'. He is pictured with his wife Sophie during a trip to India last year

The photo emerged publicly for the first time on Wednesday after a tip from a Vancouver businessman Michael Adamson who was said to be part of the West Point Grey Academy community.

Adamson didn't attend the party but came across the photo in the yearbook in July and believed it should be made public.

The photo emerged a month before Canada's general election scheduled for October 21.

Trudeau, who has been in power since 2015, is facing a tough re-election battle against the main opposition Conservatives led by Andrew Scheer.

He has been admired by liberals around the world for his progressive policies in the Trump era, with Canada accepting more refugees than the United States.

His Liberal government has also strongly advocated free trade.

Trudeau has come under fire of late following one of the biggest scandals in Canadian political history, which arose when Trudeau's former attorney general said he improperly pressured her to halt the criminal prosecution of a company in Quebec.

Trudeau has said he was standing up for jobs.

He is but the latest politician to face scrutiny over racially insensitive photos and actions from their younger days.

Virginia Governor Ralph Northam was embroiled in a blackface controversy back in February in relation to his own yearbook pictures.

Northam initially apologized but then later denied he was pictured in a 1984 medical yearbook photo that showed a man wearing blackface and another dressed in a Ku Klux Klan hood.

Virginia Governor Ralph Northam was embroiled in a blackface controversy earlier this year, which was related to 1984 medical yearbook pictures