Democratic presidential candidate Barack Obama switched from debater to fundraiser Tuesday night, making a brief appearance at a late-night gathering at Al Gore's Tennessee home.

Organizers said between 300 and 350 donors attended the event that raised about $900,000. Obama spoke mostly about his admiration for Al and Tipper Gore in his four-minute speech to guests who had paid at least $2,500 each to attend.

"One simple commitment and pledge that I'll make to you: That should we have the great honor of serving as president and first lady, that these are a couple of people we will be continuing to consult," Obama said of the former Democratic vice president.

"I can't think of two people who have been two more extraordinary citizens of the Unites States of America and of the world," he said.

Gore, who suffered a bitter defeat in the 2000 presidential election, was also brief in his introduction of Obama.

"I am so excited about what is lying ahead for our country," Gore said. But he cautioned that "We can't take anything for granted. We've got a lot of hard work to do."

"But ladies and gentlemen, I take such pleasure and pride in saying these words: The next president of the United States of America, Barack Obama!" Gore said.