Vice Presidential Candidates Prep for Their Debate

They face off on Tuesday in Virginia.

Pence told supporters he was in town doing "doing a little bit of debate prep of my own with a very good man who is putting me through my paces."

That work was confirmed by Walker on Twitter on Thursday.

ABC News has been told that Walker is formally acting as Kaine's stand-in during debate preparations.

"He is a good person to his core," he said. "And deep down, that’s what a lot of voters look to ... is this a good person. And I think he will exude that because he is what he is.”

ABC News' Jessica Hopper and Ines De La Cuetara contributed to this report.