Republican vice presidential nominee JD Vance has spent the last month engaging in intense prep sessions ahead of the debate with his Democratic counterpart, Minnesota Gov. Tim Walz, on October 1.

That preparation includes reviewing footage of the governor’s previous speeches and studying binders of research regarding his policies, a person directly involved in the debate prep told CNN.

The preparation is also expected to include a mock debate later this week with House Majority Whip Tom Emmer playing the role of Walz, while Monica Crowley – Donald Trump’s former assistant secretary for public affairs at the Treasury Department – will sit in as the mock moderator, two sources familiar with the planning said.

Vance’s team approached Emmer, a Republican congressman from Minnesota who has known Walz for years, to aid in the Ohio senator’s debate preparation, the sources said. Emmer has spent the last month studying Walz’s mannerisms and rhetoric to prepare for the role. The New York Times first reported Emmer’s involvement with Vance’s debate preparation.

Crowley, meanwhile, was enlisted by Vance’s team to give the mock debate session as “real and professional” of a feel as possible, the source with direct knowledge of the preparation said. Before serving in the Trump administration, Crowley was a Fox News contributor and occasionally sat in for Sean Hannity on his nightly show.

Vance has been working closely with his top political aides and with senior Trump adviser Jason Miller, who took the lead on the former president’s debate prep, to study for the October 1 showdown. The group has met in person at Vance’s Cincinnati home, as well as on Zoom over the last several weeks, with a focus on helping the Ohio senator better understand Walz stylistically, as well as on familiarizing Vance with Walz’s record as both a Minnesota congressman and governor, the person said.

The main goal for Vance is to needle Walz on his record, specifically his handling of the Minneapolis riots in the aftermath of George Floyd’s murder in 2020, as well as some of his more socially progressive policies, such as a 2023 law Walz signed requiring that students of all income levels and gender identities have access to menstrual products.

Vance’s frequent attacks on Walz thus far, such as questioning his military service and labeling him as a liberal in a moderate’s clothing, will also serve as key lines of messaging next Tuesday, the source said.

The Ohio senator has spent the majority of the prep sessions studying Walz specifically and less on rebuffing potential attacks aimed at him, with Vance’s team arguing that his frequent media interviews and events on the trail have already prepared him to answer for his own record.

“One of the benefits of doing hostile media nonstop is you become very well-versed in dealing with attacks on your record,” the person with direct knowledge of the preparation told CNN. “We have a lot of confidence in JD speaking about policy. The goal is to focus on Walz and his weaknesses.”

Trump’s top advisers, including campaign managers Susie Wiles and Chris LaCivita, have largely left the debate preparation up to Vance’s direct team with the exception of Miller, the sources said.

And while Vance’s team has projected confidence in the Ohio senator’s ability to debate, they insist they view Walz as a competitive opponent.

“We’re taking Walz very seriously, and having studied the footage, we expect him to be an effective debater,” the source said.

CNN’s Kit Maher contributed to this report.