First lady Michelle will also speak at the DNC, a week after Ann Romney took to the stage in Tampa, Fla., to talk about her husband, Republican presidential nominee Mitt Romney.
Mrs. Obama will make the case for re-electing the president. It's something the convention delegates are anxious to see.
"I think Michelle Obama has been a leader in this country," said Los Angeles City Controller and delegate Wendy Greuel, "and you will hear tonight what an extraordinary woman she is in her own right."
She also has a much higher approval rating than her husband, which has led to the campaign using her as its not-to-secret weapon.
"I think Michelle's mission tonight is to let people know the president is here for everyone," said delegate Alene Harris of Carson.
The race for president has been getting tighter every day. Just about every credible poll has Romney and President Obama within a few points of each other, within the margin of error. Political observers said this year, the Latino vote will matter more than it ever has.
"States like Colorado, like Florida, even like Ohio and Michigan, states with quickly growing Latino population and growing numbers of Latino voters, the Latino community could very well decide this election, and both candidates are very aware of that," said California state senator and delegate Alex Padilla.
President Obama's lead among Hispanics is more than double his lead among women at more than 40 percent.
"All you hear from the Republicans is let's cut Medicare, let's make it more difficult to register to vote and let's seal off the border. That's not a message hope and that's certainly not a message of investment in our community," Padilla said.
The problem for Democrats is the enthusiasm gap. Unlike convention delegates who are fired up, the Latino community at large is less so. Voter registration among Latinos is lagging. Tuesday night's keynote speaker is Julian Castro, the mayor of San Antonio. It will be the first convention keynote speech by a Latino in the history of either political party.
Look for ongoing reports from ABC7 Anchor Marc Brown at the Democratic National Convention in Charlotte, N.C.