The trip to North Korea, first reported by the Washington Post, happened over Easter weekend.
The White House and the CIA have declined to comment.
Earlier on Tuesday, Trump himself confirmed there have been "direct talks at very high levels with North Korea."
The president, who confirmed the meeting in a tweet Wednesday morning, has said he hopes to meet with Kim as early as May or June. Trump said Tuesday that five locations have been discussed as possible venues.
A senior U.S. official said the president has ruled out China as a location and that Kim likely wouldn't agree to meet in the U.S., just as Trump said he wouldn't meet in North Korea.
Venues in Europe, southern Asia and the demilitarized zone between North and South Korea are being considered.