Prime Minister Lee Hsien Loong along with his wife celebrated an early National Day on Sunday with more than 500 Singaporeans at the Singapore embassy in Washington, DC.

The Prime Minister is currently in the United States for an official visit and will be attending a state dinner hosted by US President Barack Obama and First Lady Michelle Obama at White House on Tuesday (Wednesday morning Singapore time).

On the occasion of National Day, Lee said: "We have much to celebrate because we have spent 50 years together and are now embarking on the next 50 years, the second half century of our nation building journey."

"The fact that we have so many Singaporeans here in America, living, working, studying, some married here, some visiting here, shows how wide and deep our relations are. And it's not just between the governments or the companies, but people too," he told Channel NewsAsia.

Other Members of Parliament and Cabinet Ministers including Minister for Foreign Affairs Vivian Balakrishnan, Minister for Trade and Industry (Industry) S Iswaran, Minister at the Prime Minister's Office Chan Chun Sing and Acting Minister for Education (Higher Education and Skills) Ong Ye Kung were also present at the National Day celebration.

The National Day festivities at the Singapore Embassy were moved earlier to coincide with Lee's official visit.

National Day songs were played in the background and Singaporean favourite dishes such as chicken rice, satay and mee siam were arranged at the celebration.

During this official trip, Lee is also expected to meet US Vice-President Joe Biden, and a few other senior US leaders such as Secretary of State John Kerry, Secretary of Defense Ashton Carter, Central Intelligence Agency Director John Brennan, Secretary of the Treasury Jacob Lew and Secretary of Commerce Penny Pritzker.