Park Geun-Hye, South Korea president, is to hold talks with President Barack Obama on her first state visit to the US.
Washington and Seoul are marking the 60th anniversary of forging their bilateral alliance, and are fresh from the most strident round of North Korean threats against them for many years.
The two countries are pledging to coordinate closely in their approach, and both have offered talks to the North, so far without reward.
North Korea is likely to top Tuesday's agenda, and the positon of China is also likely to be raised.
Al Jazeera's Harry Fawcett reports from Seoul.