WASHINGTON — Democrats will hear from three presidents at their convention next week in Chicago, where they will gather to recognize Vice President Kamala Harris as their nominee and celebrate an unexpected campaign that has turned the race on its head.

President Joe Biden is expected to address delegates Monday, the convention’s first night, with former President Barack Obama speaking Tuesday, according to three people familiar with the planning who insisted on anonymity to discuss sensitive arrangements.

Former President Bill Clinton and former Secretary of State Hillary Clinton, the party’s 2016 nominee, will also speak at the convention, two of the people said.

Harris’ running mate, Gov. Tim Walz of Minnesota, has been given a Wednesday speaking slot. And Harris will ceremonially accept the nomination Aug. 22, the convention’s grand finale.

A formal speaking schedule has not yet been released. Neither has the identity of the convention’s keynote speaker, a high honor often bestowed on a rising star in the party. Past keynote speakers at Democratic conventions have included Obama in 2004; Julián Castro, then the mayor of San Antonio, in 2012; and Sen. Elizabeth Warren of Massachusetts in 2016. At the party’s virtual 2020 convention, a medley of younger Democrats gave a group keynote address via video.

Since taking over from Biden, Harris has transformed the contest against former President Donald Trump, raising hundreds of millions of dollars, drawing tens of thousands of people to rallies and significantly improving on Biden’s standing in polls.

What just a few weeks ago seemed a certain defeat for Democrats in November now has all the feelings of a close race.

Conventions are usually a place for a party’s ambitious hopefuls to try to shine in anticipation of the next election cycle.

At a convention for Biden, 81, that would have been doubly true, with younger Democrats like Harris, California Gov. Gavin Newsom, Michigan Gov. Gretchen Whitmer and Secretary of Transportation Pete Buttigieg all vying for the limelight.

But Harris’ ascent to the top of the ticket has put 2028 on the back burner for now.

And while a convention focused on Biden would almost surely have suffered from the lack of enthusiasm that pervaded his campaign, Harris’ is likely to be more festive. Hip-hop and hipster rock stars have graced her rallies, and numerous celebrities have come out in support of her bid.