It's the first known plan to bring together the victor and vanquished from the Democrat primary race and put their pledges of unity for the fall campaign into action.
Jonathan Mantz, Clinton's national finance director, sent top Clinton fundraisers an e-mail today inviting them to the event on June 26.
"As we move forward, we invite you to join us for a National Finance Committee meeting with both Hillary Clinton and Barack Obama on Thursday, June 26th in Washington, D.C., to discuss how we can work together to support Barack Obama and the Democratic Party," Mantz wrote.
"Hillary ran for President because she wants to put this country on the right track," Mantz wrote. "She continues to fight and stand strong for our values and priorities and will do everything she can to unify the party and to elect Barack Obama the next President of the United States."
As part of the effort, Mantz wrote, the Clinton campaign is encourage its supporters to contribute $2,300 to Obama's campaign.
The event will be held at the Mayflower Hotel.
On June 7, Clinton suspended her campaign and endorsed Obama for President. At the time, she encouraged her supporters to follow her lead and throw their support behind the presumptive Democratic nominee.
Since then, the two camps have been talking about what role Clinton will play in the campaign and how best to unify the party. This event in Washington marks a major step forward.
Clinton is scheduled to hold a conference call with donors on Thursday."They're trying to do the right thing," said one Clinton supporter, referring to the Clintons plans to help Obama. "Whether they're ecstatic about it or not, I don't know."