Barack Obama made a surprise appearance Wednesday at the Democratic National Convention, but it was just a warm up for the history making moment that awaits him tonight when he becomes the first black man to accept the presidential nomination of a major political party.
Obama will claim the nomination tonight before a crowd so large the convention will be moved to a 70,000 seat sports stadium, Invesco Field. Adding poignancy to his remarkable moment, he will become the party's leader on the 45th anniversary of Martin Luther King Jr.'s "I Have a Dream Speech."
The Democrats' new leader popped out of the wings Wednesday night after a rousing speech by his vice presidential candidate, Joe Biden.
As delegates roared inside the Pepsi Center in Denver, Obama referred to a speech by his wife on Monday: "I think Michelle Obama kicked it off pretty well, don't you think?" he said.
Michelle Obama mouthed, "I love you," from her skybox seat.
"If I'm not mistaken, Hillary Clinton rocked the house down last night!" Obama said, referring to his chief rival for the Democratic nomination, who addressed the convention Tuesday.
Obama even offered praise for Bill Clinton, who had been aggressive toward Obama on the campaign trail, but enthusiastically endorsed of the Democratic nominee before the convention crowd earlier Wednesday.
Obama called Clinton "someone who reminds us what it's like when you've got a president who actually puts people first. Thank you, President Clinton."
A night that could have been all about former President Clinton's speech now also will be remembered for Obama's appearance.
Obama walked out onto the stage after Biden praised his Democratic ticket mate and delivered an aggressive attack on their Republican rival, John McCain.
Watch Charlie Gibson, Diane Sawyer and George Stephanopoulos at the Democratic Convention TONIGHT at 10 p.m. ET on ABC.
Democrats earlier made Obama's nomination official when party delegates formally picked him as their 2008 presidential candidate, making Obama the first African-American ever nominated by a major party.
Obama was at a Denver hotel with his wife, Michelle, and his daughters Malia, 10, and Sasha, 7, and extended family when he learned that he was officially the nominee.
A woman delegate was seen weeping as Obama's primary rival Sen. Hillary Clinton moved to nominate Obama by acclamation.
Obama's campaign manager David Plouffe said the candidate was moved by the moment.
"Even though we became the presumptive nominee some time ago, it became reality last night. And to see Sen. Clinton be so gracious in moving our nomination by acclamation, and really to see the eruption in the hall and the sheer sense of joy and excitement about the election was really a special moment," Plouffe told "Good Morning America."
Hollywood stars and musicians were in the audience as history was made. Director Steven Speilberg and his wife Kate Capshaw sat in a skybox. Musician Melissa Etheridge performed "God Bless America."
Biden was formally nominated as the party's vice presidential candidate Wednesday, as well. His nomination was seconded by his son, Beau, as more than two dozen additional family members joined them in the convention hall, including Biden's 92-year-old mother, Jean.