President Donald Trump is vowing to stay out of U.K. parliamentary elections set for this month but is praising incumbent Prime Minister Boris Johnson's leadership.

Trump says he and Johnson will meet during the two-day NATO leaders' meeting in London, although the White House has not announced a sit-down.

While the British premier and Trump have a friendly relationship, Johnson is trying to keep Trump, who is unpopular in the U.K., at arms-length ahead of the Dec. 12 elections.

"I don't want to complicate it," Trump told reporters at the start of a meeting with NATO Secretary-General Jens Stoltenberg.

Trump added that he's a "fan" of Brexit and said he knows "nothing" of Johnson's Labour Party rival Jeremy Corbyn.

He described Johnson as "very capable" and said "he will do a good job."

Johnson is set to host Trump and other NATO leaders at a reception in London later Tuesday.