US President Donald Trump is visiting South Korea amid hopes of new talks to end the North's nuclear programme.
The US leader is set to arrive in South Korea for a two-day visit on Saturday.
He will meet President Moon Jae-in on Sunday, following a summit of G20 leaders in Japan, according to Mr Moon's spokeswoman.
They will hold "in-depth discussions on ways to work together to foster lasting peace", the spokeswoman said.
It comes after an exchange of letters between President Trump and North Korean leader Kim Jong Un, which boosted hopes for talks aimed at ending North Korea's nuclear program.
President Trump told reporters at the White House on Monday that President Kim had sent him birthday wishes.
"It was just a very friendly letter both ways. We have a very good relationship," he said.
US Secretary of State Mike Pompeo said he hoped a letter Mr Trump sent to the North Korean leader could pave the way for a revival of stalled nuclear talks.
Mr Pompeo, who spoke of Mr Trump's letter before departing from Washington for the Middle East, said the United States was ready to resume talks with North Korea immediately.
"I'm hopeful that this will provide a good foundation for us to begin ... these important discussions with the North Koreans," he said.
During his visit, Mr Trump is considering a visit to the demilitarized zone (DMZ) separating the two Koreas, a South Korean official said.
Mr Trump wanted to go there during a 2017 trip to South Korea but heavy fog prevented it.
There has been some speculation of a meeting with the North Korean president there, though another official in the South Korean presidential office said she was not aware of any plan for that.
Mr Trump and Kim held their first summit in Singapore in June last year, agreeing to establish new relations and work towards the denuclearisation of the Korean Peninsula.
But a second summit in Vietnam in February collapsed.
This came as the two sides were unable to bridge differences between US demands for denuclearisation and North Korean demands for sanctions relief.
Additional reporting by agencies.
