Former US president Barack Obama on Wednesday urged Canadian voters to back Prime Minister Justin Trudeau for another term, calling him an "effective leader."
"I was proud to work with Justin Trudeau as President. He's a hard-working, effective leader who takes on big issues like climate change," Obama said in a tweet.
"The world needs his progressive leadership now, and I hope our neighbours to the north support him for another term."
Trudeau, who is running neck-and-neck with Conservative leader Andrew Scheer ahead of the October 21 ballot, tweeted back: "Thanks to my friend, we're working hard to keep our progress going."
His Liberal Party also promoted the endorsement on social media.
The pair first met as leaders of their respective countries at an Asia-Pacific Economic Cooperation (APEC) summit in November 2015, one month after the Canadian won his first general election.
Four months later, Trudeau became the first Canadian leader in 20 years to make an official pomp-filled visit to the White House.
The warmth of the encounter triggered a flood of online jokes and tongue-in-cheek reports of a budding "bromance" between the two men.
Obama saluted Trudeau as his political and generational kin, even though the American is 10 years older. Both champion the importance of issues like health care, gay rights and climate change.
"He campaigned on a message of hope and of change," Obama once said. "From my perspective, what's not to like."
They last met for a beer reportedly in May when Obama was in Ottawa to deliver a speech.
Their relationship stands in stark contrast to Trudeau's troubled ties with current US President Donald Trump.