It's the first ever meeting between a sitting US president and North Korean leader.
The meeting is the first sit-down between a sitting US president and North Korean leader and is meant to settle a standoff over Pyongyang's nuclear program.
The two will huddle alone for roughly 45 minutes before being joined by aides for a larger meeting and working lunch.
It's Kim's pursuit of nuclear weapons that gives his meeting with Trump such high stakes.
So you can only imagine how much Singapore is paying to have the North Korean leader and an entire army of bodyguards and government officials at the St. Regis.
Trump's early exit will be his second from a summit in just a few days.
"The entire world is watching the historic summit between (North Korea) and the United States of America, and thanks to your honest efforts. we were able to complete the preparations for the historic summit", Kim told Lee through an interpreter. Traffic was held up in the steamy midday sun and scores of bystanders were penned in by police when Trump went to meet Lee.
When Singaporean Prime Minister Lee Hsien Loong visited the worldwide media center for the summit at F1 Pit Building on Sunday, he said it will cost the city state "around 20 million Singaporean dollars" (W16.1 billion, US$1=W1,078) to host the "historic summit". Her earlier trip to South Korea in January triggered a media frenzy.
It's unclear what Trump and Kim might decide Tuesday. Again accusing the longtime U.S. ally of unfair trade practices, Trump added: "Then Justin acts hurt when called out!"
Laboriously negotiated past nuclear deals, considered breakthroughs at the time, broke down on North Korea's extreme sensitivity to allowing in outsiders to look at whether they're dismantling their nuclear facilities, many of which are thought to be hidden.
Trump and Kim arrived in Singapore hours apart Sunday.
It was a striking about-face from less than a year ago, when Trump was threatening "fire and fury" against Kim, who in turn scorned the American president as a "mentally deranged USA dotard".