Speakers will include Donald Trump, Jr., Florida Governor Ron DeSantis, South Dakota Governor Kristi Noem, and Iowa GOP Chairman Josh Kaufmann.
Sources also told ABC News that former first lady Melania Trump is expected to attend, but it's not yet clear if she's going to speak.
Security preparations are ramping up for the convention as crews install metal barriers to distinguish the different security zones.
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Project 2025 continues to hang over the RNC, a sweeping plan from conservative groups to overhaul the federal government.
When Republicans meet in Milwaukee next week, they will vote to officially confirm the new party platform, which has been crafted by individuals with deep ties to Project 2025.
Project 2025 initiatives include expanding presidential power, drastically cutting federal agencies like the Department of Education, a plan to fire as many as 50,000 government workers to replace them with Trump loyalists, and restricting abortion access.
READ MORE: Trump is trying to distance himself from Project 2025. Its architects helped shape his RNC platform
Heritage Foundation President Kevin Roberts said on Steve Bannon's "War Room" podcast on July 2 that Republicans are "in the process of taking this country back." Former U.S. Rep. Dave Brat of Virginia hosted the show for Bannon, who is serving a four-month prison term.
"We are in the process of the second American Revolution, which will remain bloodless if the left allows it to be," Roberts said.
Those comments were widely circulated online and assailed by Biden's campaign, which accused Trump and his allies of "dreaming of a violent revolution to destroy the very idea of America."
MORE COVERAGE: RNC committee adopts GOP's 2024 policy platform
Former President Trump has been attempting to distance himself from Project 2025 recently, but some of the people involved in Project 2025 are former senior administration officials. The project's director is Paul Dans, who served as chief of staff at the U.S. Office of Personnel Management under Trump. Trump's campaign spokeswoman Karoline Leavitt was featured in one of Project 2025's videos.
John McEntee, a former director of the White House Presidential Personnel Office in the Trump administration, is a senior adviser. McEntee told the conservative news site The Daily Wire earlier this year that Project 2025's team would integrate a lot of its work with the campaign after the summer when Trump would announce his transition team.
The Associated Press contributed to this report.