On "The O'Reilly Factor" tonight, Bill O'Reilly asked Donald Trump if he's nervous about Thursday's Fox News-Facebook Republican presidential debate.

Trump acknowledged that the debate is a big deal and he is a little apprehensive.

"You don't know what's going to come at you, you don't know where these other people are going to come [from]," Trump said of his fellow GOP contenders.

He added that he also doesn't know what kind of the questions the moderators of the debate, Megyn Kelly, Bret Baier and Chris Wallace, might ask.

"All of that has nothing to do with being a great president," Trump said. "But I'm doing it because it's something you have to do."

"And again, I've never debated. Sort of, my whole life has been a debate, but I've never debated before. These politicians, all they do is debate."

Watch the must-see "Factor" interview  above.

Don't miss the Fox News-Facebook Republican presidential debate, Thursday August 6, live from Cleveland, Ohio at 8:50p ET, moderated by Megyn Kelly, Bret Baier and Chris Wallace. 

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