Even if it doesn’t come up during the interview—which it likely will, if only obliquely—what Fox has called Trump’s “obsession” with Kelly will be a kind of sub-text running beneath the event. For reasons known only to Trump, the former Celebrity Apprentice host decided to target the Fox anchor for ridicule and outright abuse well before he became the front-runner for the Republican presidential nomination.

The drama began with the very first Republican debate last August, when the Fox anchor asked the candidate whether he had the right temperament to be president, given that he had referred to women using derogatory terms such as “fat pigs” and “disgusting animals.” A day later, Trump made a comment about Kelly having blood “coming out of her wherever,” which many took to be a reference to the menstrual cycle. (Trump denies this.)

Over the following weeks, Trump said he didn’t respect Megyn Kelly, called her a “bimbo,” and said that her show had gone downhill and she didn’t know how to ask tough questions. He accused her of being unbalanced, and called her a “light-weight.” At one point in late August, Fox chairman Roger Ailes released a public statement that said Trump’s “unprovoked attack” on Kelly was “as unacceptable as it is disturbing.”

Undeterred, Trump continued to criticize Kelly (and other Fox hosts as well) through the fall, referring to Kelly as “dopey,” and calling her reporting into question on Twitter and elsewhere. In January, he said he was reconsidering whether to take part in a Fox News debate with Kelly as moderator, and then announced that he would not attend. Trump’s campaign manager sent a threatening email aimed at Kelly, and Fox made a public statement saying it refused to “give in to terrorizations toward any of our employees.”

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Trump continued his Twitter offensive against Kelly for the next several months, sniping at her and at Fox in general, and then he went quiet. In mid-April, it emerged that Kelly had met with Trump at his office in New York—a meeting that Kelly instigated—and that they had achieved a kind of truce. Two weeks later, Fox announced that Trump and Kelly would have a full-blown interview during prime-time on May 17, and that the show would be on the main Fox network, not Fox News.

Befitting a campaign in which the leading candidate is known for a TV show that blurred the lines between reality and scripted TV drama, there are any number of sub-texts and counter-narratives in Trump’s attack on Kelly. For Trump, targeting the Fox anchor appears to have been partly a way to distance himself from Fox, a network that has traditionally been seen as the home of mainstream political conservatism. By doing so, the theory goes, Trump was able to broaden his appeal beyond the traditional Republican audience, and also pick up points with those who didn’t like Kelly.

For Kelly, meanwhile, Trump’s relentless attacks—as painful as they may have been personally—have served to put her in the spotlight in a way she might never have been otherwise, and that has undoubtedly helped her career, both within Fox and potentially outside of it. Her contract with Fox comes up for renewal next year (she reportedly makes more than $6 million a year at Fox), and there has been much talk about the opportunities that might await her.

Paul Ryan discusses his meeting with Donald Trump. Watch:

Those kinds of business realities are almost certainly part of the reason Kelly tried to mend fences with Trump in April, convincing him to sit down for Tuesday’s chat. Like it or not, her career and Trump’s are joined at the hip. And even from a purely journalistic point of view, it’s not great for a prominent news anchor to get frozen out by the leading Republican candidate for president.

In the larger sense, close watchers of billionaire Rupert Murdoch­—who owns 21st Century Fox and thus Fox News—say the media mogul was an early critic of Trump and his candidacy, which helped drive a wedge between Trump and Fox. More recently, however, Murdoch appears to have softened his stance because of Trump’s success at becoming the front-runner for the Republican nomination. So Fox and Ailes are clearly invested in having Kelly strike some kind of truce with Trump as well.

In a very real way, the Fox anchor and the Republican candidate have created a kind of marriage of convenience for the TV cameras: Trump’s independence from Fox served its purpose as his campaign was building up steam, but he needs the network now that the campaign is heading into its final stages. And Kelly needs to show that she can command a prime-time audience and also conduct a strong, critical interview with the man who will almost certainly become the Republican Party’s nominee.