Former President Clinton does not plan to appear with his wife and Obama, ceding the spotlight to the two former foes.
The rally will be the day after Obama and Clinton meet privately Thursday at a Washington hotel with former Clinton donors. The former first lady will introduce Obama to her financial backers who have been slow to embrace her one-time opponent.
Clinton, a New York senator, suspended her campaign for the Democratic nomination earlier this month after Obama, an Illinois senator, secured enough delegates to clinch the nomination. "I endorse him and throw my full support behind him," she said at the time.
Clinton spokesman Mo Elleithee said she will make the same pitch to her supporters that they should support Obama "with everything we still need to accomplish and with the stakes as high as they are."