Former President Donald Trump and Vice President Kamala Harris have never actually met. That changes Tuesday when both presidential candidates stand next to each other on the Philadelphia debate stage.
While this is Harris' first general election presidential debate, it's not her first time high-profile event. In the past, she has not been afraid to engage opponents or those testifying before her.
However, Harris will not be able to ask Trump direct questions Tuesday night. The ABC rules state only moderators can.
As for Trump, after Tuesday he will hold the record for participating in the most televised general election presidential debates. And in the past, he hasn't been afraid to attack or interrupt his opponents.
Interruptions are expected to be minimal Tuesday because microphones will be muted when the other candidate is speaking — like the CNN debate between Trump and President Biden in June.
Former Trump advisor Hogan Gidley says he expects Trump make Harris' campaign pledges a focal point of attack Tuesday night.
"She can't avoid reality. She has been the vice president for years," Gidley said. "So anytime she speaks in the future, 'I promise I will,' 'on day one we will' — You are the vice president now, so if you won't do them now, that's pretty cruel or you can't do them."
Gidley added that Trump's preparations have included campaign events and peppering staff with questions behind the scenes.
Harris' preparations has been more traditional. She's spent the past few days hunkering down with aides in Pittsburgh practicing debate scenarios.
Jarvis Stewart is a Democratic strategist close to the Harris campaign and says she'll be ready.
"She is ready to demonstrate strength," he said. "Demonstrate that she is not only the smartest kid in the room, but can also be a great bully on the playground. So there is a great balance there."
June's debate between Biden and Trump drew over 50 million viewers. Similar numbers are expected this time around.
