Harris-Trump debate live updates: Stage set for showdown in tight presidential race

Harris said in an interview that aired Monday that she expects former President Donald Trump to lie during the ABC News presidential debate on Tuesday.

Meanwhile, the Trump campaign and surrogates continued to insinuate on Monday that the former president's strategy at the debate will be to tie Harris to what they say are her policy failures and "disasters" as a leader of the Biden-Harris administration.

With time ticking down until the two meet for the debate, both candidates are working to spin expectations in what is expected to be a key moment for both campaigns as they look to appeal to voters ahead of what's expected to be a close contest in November.

Read more here.

-ABC News' Gabriella Abdul-Hakim, Fritz Farrow, Will McDuffie, Mary Bruce and Oren Oppenheim

Gold Star father Khizr Khan, whose son Humayun Khan was a Muslim Army captain who was killed during the Iraq War in 2004, will be among the surrogates supporting Harris in the spin room at the debate, a campaign official confirmed to ABC News.

Khan garnered national attention after he delivered a blistering speech attacking Trump at the 2016 Democratic National Convention.

Harris will also be supported in the spin room by retired Brig. Gen. Steven M. Anderson, according to the campaign official. NBC News first reported Khan and Anderson's roles as Harris surrogates in the spin room.

-Fritz Farrow, Grabriella Abdul-Hakim and Will McDuffie

Trump campaign spokesperson Danielle Alvarez said Tuesday morning on ABC News Live that Trump "does not do traditional debate prep" and reiterated that he has been campaigning and engaging in policy discussions instead.

"I would say that the president does not do traditional debate prep. He's on the campaign trail constantly. We see him in key battleground states every week, joined by tens of thousands of patriots," she said. "We know that he does tough interviews, both nationally, locally."

"That's truly how he prepares for these debates, having those conversations every day. He's ready to step back into the White House," she continued. "We also know that he prefers to have those policy discussions, and he's been doing that with elected members in Congress like Matt Gaetz, with former Congress member Tulsi Gabbard and others -- very similar to what he did to prepare for that first debate against Joe Biden. He has prepared in a similar way again, just by getting out there and talking every day to voters and talking to media."

-ABC News' Soorin Kim, Lalee Ibssa and Kelsey Walsh

Just hours away from the debate, a campaign source is setting expectations that Harris is not "underestimating" Trump's ability to debate, and that it would be a "mistake" to do so.

The Harris team expects Trump to be "good" at debating, stressing that Trump has done this more than anybody else, while it will be Harris's first presidential debate.

The Harris campaign is "happy to get under [Trump's] skin," and they hope that bringing former Trump officials into the spin room later this evening will accomplish this.

On a campaign call last night, a source said Harris is ready for any version of Trump that shows up -- whether it's the presidential Trump, the more mellow Trump during the Biden debate or a more aggressive version.

-ABC News' Selina Wang