(CNN) Joe Biden is poised to make his long-awaited announcement to jump into the 2020 presidential campaign next week, people close to the former vice president say.

The format and date of the announcement are still in flux, but Biden's team has been quietly laying the groundwork for a presidential campaign for months.

While his deadline has slid back several times this year, people close to the Delaware Democrat say they expect him to join the Democratic primary fight next week.

Greg Schultz, a top political adviser who is preparing to oversee Biden's campaign, told Democrats on Capitol Hill earlier this week that "everything is going ahead as scheduled."

His entry into the race will answer one of the biggest remaining questions of the makeup of the crowded and historically diverse Democratic primary field. This would mark his third run for the White House.

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