" The discussions between the United States and North Korea are ongoing and have moved more quickly than expected," read a White House statement.

The White House said both the leaders will remain engaged in a one-on-one discussion with each other.

"President Donald J. Trump will meet with North Korean leader Kim Jong Un tomorrow morning at 9:00 a.m.  Following the initial greeting, President Trump and Chairman Kim will participate in a one-on-one meeting, with translators only, an expanded bilateral meeting, and a working lunch," it said.

The United States delegation on Tuesday's expanded bilateral meeting will include Secretary of State Mike Pompeo, Chief of Staff John Kelly, and National Security Advisor John Bolton.  Press Secretary Sarah Sanders, Ambassador Sung Kim, and National Security Council Senior Director for Asia Matt Pottinger will join for the working lunch.

Trump arrived in Singapore on Sunday for the meeting.

He tweeted: " Great to be in Singapore, excitement in the air!."

Trump, earlier in the day, met Singapore Prime Minister Lee Hsien Loong.