According to a report from Axios, U.S. President Donald Trump sent an unorthodox note to Canadian Prime Minister Justin Trudeau.

According to the report, the Canadian ambassador who’d received it did a double-take, questioning the note’s validity.

Several sources have reported that the two have exchanged handwritten notes before.

Axios reports that one of the strange notes was a torn-out Bloomberg Businessweek cover featuring Justin Trudeau, where the headline read “The Anti-Trump.” Sources say that Trump grabbed a sharpie and wrote, “Looking good! Hope it’s not true!”

The letter went through typical clearance protocol, via the National Security Council. Staffers reportedly believed that this was an odd form of communication with a foreign leader, but allowed it to go through, as it was done in good fun.

One of the letters sent to Trump from Trudeau was around the Christmas season of 2017, shortly after Trump had stated on stage that the U.S. had a trade deficit with Canada. The letter read, “Dear Donald, it’s been a busy year! Enjoy the Christmas holidays—you deserve it.”

“One thing,” Trudeau added. “You gave a great speech in Pensacola, but you were slightly off on the balance of trade with Canada. USTR says so! All the best for 2018, Justin.”

It seems as though the two may have developed a friendly “off-screen relationship,” though that is entirely speculatory.