Hillary Clinton plans to join Barack Obama on the campaign trail for the first time next week, a sign to her supporters that it's time to unite behind the presumptive Democratic nominee after a bitter primary.

The Obama campaign sent out a brief e-mail Friday morning announcing the two former rivals would campaign together June 27. The e-mail said more details are forthcoming.

A day before they campaign, Obama and Clinton also plan to meet in Washington with some of her top contributors in an effort to calm donors frustrated with Obama's campaign. The former first lady will introduce Obama to her financial backers.

The New York senator urged her party to close ranks behind Obama when she bowed out of the race two weeks ago -- but since then she has kept a low profile.

So has Bill Clinton, who was his wife's most vigorous surrogate when she was running for the nomination.

The former president, though, is not expected to campaign with the new standard bearer of the Democratic Party next week.

Matt McKenna, spokesman for the William J. Clinton Foundation, told FOXNews.com that Clinton will be in Europe next week speaking on behalf of his foundation and attending Nelson Mandela's 90th birthday party. He said the former president will also make a "major announcement" with the British government.

McKenna said there are no immediate plans for Clinton to join up with Obama on the campaign trail.

“He’s had a couple of days off. He's obviously been going pretty much non-stop for several months," McKenna said. "But for the most part he’s right back at work doing foundation stuff.”

Several high-profile Clinton backers, including Pennsylvania Gov. Ed Rendell and others, have come out to support Obama since it became clear early this month that Obama had enough delegates to secure the nomination.

While the Clintons have stayed quiet, her supporters are pushing for Obama to tap her as his running mate given her strong performance during the marathon 50-state primary race.

That is seen by some backers as a way to help heal the divisions of the primary season. But Obama reportedly is considering many current and former senators, governors and military officials and dampened some of the Clinton speculation when his campaign announced that her former campaign manager Patti Solis Doyle would be joining as chief of staff for his yet-to-be-named vice presidential pick.

Solis Doyle left the Clinton campaign after she suffered a series of defeats to Obama.

Obama's campaign disclosed the joint appearance with Clinton -- but offered few details -- one day after announcing he would reverse an earlier position and reject some $85 million in public financing for the general election. That announcement opened him up to a flood of criticism and dominated the news cycle.

Thus, Obama's campaign sought to redirect attention by putting word out a full seven days in advance that Obama and Clinton would campaign together.

Clinton ended her campaign on June 7, four days after Obama got enough delegates to clinch the nomination. "I endorse him and throw my full support behind him," she said at the time.

The two met privately on June 5 after ditching reporters to make sure there would be no photos or coverage of the first post-race meeting. Obama was asked Wednesday whether they were talking.

"I have not had conversations with Sen. Clinton because she has been getting a well-deserved vacation," he said at the time. "We will be speaking, I think, in the next few days or certainly the next week and will be having an ongoing conversation."

FOXNews.com's Judson Berger and The Associated Press contributed to this report.