This really is one for the history books.

Republican front-runner for president Donald Trump declared Tuesday that he would oh-so-definitely-not be participating in the next GOP primary debate, scheduled for Thursday night.

"He's definitely not participating in the Fox News debate," Trump spokesperson Corey Lewandowski told the Washington Post. "His word is his bond."

Earlier, Trump made rumblings he would not participate in the debate if Fox News' Megyn Kelly was moderator. 

RELATED: Trump fever grips GOP, billionaire leads with 40 percent support: Poll

Trump has, in the past, called Kelly "a third-rate reporter who is bad at her job," according to the New York Post. In fact, the Kelly-Trump affair is such a thing that Entertainment Tonight created a video timeline of the feud.

Though, to be fair, a feud typically has two participants. In this case, it seems like the "feud" is mostly one-way from Trump's direction.

"The feud between Trump and Kelly first started last August at the very first Republican presidential debate," ABC News explained. "The two had a contentious back-and-forth."

Contentious is putting it mildly based upon the reaction Donald Trump had after the debate on Twitter – or, to put it another way, when he was safely behind his smartphone screen and not on the debate stage face-to-face with Kelly.

RELATED: British parliament debates voting Donald Trump off the island

Trump has even gone on the offensive against Kelly, randomly tweeting about her critically literally months after the August debate. 

So, when Fox News planned to have Megyn Kelly moderate Thursday's debate, Trump began his swagger, signaling that he, who admittedly boosts television ratings, might not participate. Fox News insisted that, no matter what Trump does, Kelly would be moderating.

"Megyn Kelly is an excellent journalist, and the entire network stands behind her," Fox News head Roger Ailes said in a statement to the Washington Post on Tuesday. "She will absolutely be on the debate stage on Thursday night."

In response, Trump flatly stated Tuesday he wasn't showing up.

So there