WATCH: Did Donald Trump just hint that Bill O’Reilly fed him questions before Fox News interview?

Fox News host Bill O'Reilly had his big interview Monday night with GOP presumptive nominee Donald Trump, and if it seemed scripted there might be a reason for that.

“The Boston Globe writes that you pay men in your campaign a third more in salary than you pay women..." O’Reilly began his question to Trump. “Is that true, do you pay men a third more than women in your campaign?”

“The answer is no,” Trump said before accidently revealing he got the questions. “And I just had it checked because I heard this was going to be a question. I don’t know, I have a good source and somebody said this could be a question. I just checked it, Bill, and the answer is no,” he said.

Trump flips between "heard this was going to be a question" and "this could be a question," which draws a distinction between he got the questions ahead of time or he was prepped by his staff ahead of time on what could come up. Most candidates who do a lot of interviews with press get drilled by their communications staff ahead of the interview.

The Society of Professional Journalists lists in its code of ethics that journalists should be both independent and transparent.

According to their guidelines, journalists such as O'Reilly should "deny favored treatment to advertisers, donors or any other special interests, and resist internal and external pressure to influence coverage." An argument could be made that giving Trump the questions ahead of time would qualify as "favored treatment" to "influence coverage."

Similarly, they suggest journalists be transparent about their process, saying they should "explain ethical choices and processes to audiences." At no point in O'Reilly's interview did he discuss or disclose whether Trump received questions ahead of time.

UPDATE: Fox News’s David Tabacoff, Senior Executive Producer of the O'Reilly Factor responds:

"We never, ever tell the guests what questions will be asked. Bill O'Reilly is the only person who knows what exactly he'll ask. We treated this interview like we treat all other guests on the program."

Check out the interview below via FoxNews: