Barack Obama and his wife Michelle arrived at the White House for coffee with outgoing president George W. Bush and his wife Laura just two hours before his inauguration.
The two leaders and their wives posed for photos as the world waited eagerly for Mr Obama to take over as America's president
The meeting came after Mr Obama and his family attended a private service at St John's Episcopal Church, a tradition for those about to become president.
A smiling Mr Obama seemed calm and relaxed just hours before becoming the 44th president of the US while Mrs Obama showed slight signs of nerves as she initially went to shake hands with Mr Bush first, instead of with his wife.
She also handed Mrs Bush a present in a cream box, wrapped in red ribbon.
Inside the White House, the two couples drank coffee together before travelling the short distance to the Capitol for the transfer of power.
Just beyond the White House fence, huge crowds braved freezing temperatures of minus and jostled for the best positions ahead of the inauguration.
Earlier, the Obama family attended a private service at St John's Episcopal Church, a tradition for those about to become president. The family of Vice President-elect Joe Biden also attended.
Barack and Michelle Obama waved to bystanders, then entered the church to applause from about 200 people. The choir and congregation began singing the hymn,
O God Our Help in Ages Past.
The Reverend Luis Leon welcomed the Obamas and said every president since James Madison has worshipped at the church at least once, "some of them kicking and screaming".