The Canadian prime minister, 51, said in an Instagram post that the decision was made after "many meaningful and difficult conversations".

Mr Trudeau and the 48-year-old former model and TV host married in late May 2005 and have three children - Xavier, 15, Ella-Grace, 14, and nine-year-old Hadrien.

He said in a statement: "Sophie and I would like to share the fact that after many meaningful and difficult conversations, we have made the decision to separate.

"As always, we remain a close family with deep love and respect for each other and for everything we have built and continue to build."

Mr Trudeau's office said the two had signed a legal agreement.

"They have worked to ensure that all legal and ethical steps with regards to their decision to separate have been taken, and will continue to do so moving forward," it said.

The pair met as children when Sophie was a classmate of his youngest brother, Michel, and they reconnected as adults when they co-hosted a 2003 charity gala.

After Mr Trudeau became prime minister in late 2015, he and Sophie were often seen together at social functions and on foreign trips.

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Together, they brought star power to the prime minister's office and appeared in the pages of Vogue magazine.

But in recent years, the first lady has played a less visible role, rarely travelling with the prime minister on official trips.

However, the two of them did travel to London in May for the coronation of King Charles and were together when US President Joe Biden visited in late March.

Mr Trudeau is the second prime minister to announce a separation while in office. His father, Pierre Trudeau, and mother, Margaret Trudeau, separated in 1979 and divorced in 1984 during the elder Trudeau's final year in the prime minister's office.