TORONTO -- With less than a week until election day, former U.S. president Barack Obama has waded into the fray to bolster the campaign of Liberal Leader Justin Trudeau, who he describes as his "friend."

On Thursday afternoon, the popular former politician shared a tweet in which he appeared to reveal who he thinks should be Canada’s next prime minister.

“Wishing my friend @JustinTrudeau the best in Canada’s upcoming election. Justin has been an effective leader and strong voice for democratic values, and I’m proud of the work we did together,” Obama wrote.

Obama was referring to the period when he and Trudeau led their respective countries at the same time, from November 2015 to January 2017.

The two politicians’ close working relationship was well-documented during this period, with some in the media dubbing it a “bromance.”

Even after Obama left office, the pair have maintained friendly relations, with the former president visiting Trudeau at an Ottawa brewery for a pint in June 2019.

Later that year, Obama tweeted his support for Trudeau during that federal election, describing him as “a hard-working, effective leader.” 

On Friday, former U.S. secretary of state and presidential candidate Hillary Clinton echoed Obama’s words with her own tweet in support of Trudeau.

“I have seen my friend @JustinTrudeau show leadership in the fight for accessible child care, protected reproductive rights, and ambitious climate action. I’m wishing him and our progressive Canadian neighbors the best in Monday's election,” she wrote.

In August, Trudeau said he had spoken with Clinton about their concern for Afghan women and girls following the Taliban’s takeover.

“[Clinton] shares our concern for Afghan women and girls. She welcomed our efforts and urged Canada to continue our work. Governments, international organizations and civil society must continue to work together to support women and girls in Afghanistan,” he said at the time.

Hours later, NDP Leader Jagmeet Singh received his own endorsement from south of the border, via Sen. Bernie Sanders.

"There's one party that stood up for working people in the pandemic. One leader who has the courage to make the wealthy pay their fair share so everyone gets the medication they need," the Independent senator for Vermont, who twice sought the Democratic Party nomination for U.S. president, tweeted.

Trudeau’s main rival in the current election, Conservative Leader Erin O’Toole, recently received an endorsement of his own -- from a former Canadian leader instead of a former American one.

On Wednesday, former prime minister Brian Mulroney joined O’Toole at a campaign stop in Orford, Que. where he described the Conservative candidate as “steady, strong, and visionary.”

Mulroney, who was prime minister between 1984 and 1993, added that he wasn’t there to attack anyone and that he only wanted to “help elect Erin O'Toole as the next prime minister of Canada.”

According to the latest polling data from Nanos Research, the Liberals and Conservatives are neck-and-neck in the campaign with no clear frontrunner in the final days leading up to the election.