The Fox News host tweeted about her frustration Friday.

SHOW TRANSCRIPT

"Hillary Clinton went on record, called yours truly 'a superb journalist' when Trump was attacking me. Why won't she come on 'The Kelly File'?" Megyn Kelly asked Hillary Clinton campaign press secretary Brian Fallon after the debate Monday.

The Fox News host really wants Clinton to come on her show.

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And this tweet makes it pretty clear she's frustrated that Clinton hasn't accepted her invitation yet. Apparently, the tipping point was that Clinton did a 30-minute interview with a singer, rather than a journalist like Kelly.

So why would Kelly be so frustrated?

For starters, Kelly's colleagues Bill O'Reilly and Bret Baier have both gotten interviews with Clinton.

According to TVNewser, Kelly has the second most watched cable news show — behind O'Reilly. But she has the most watched cable news show among the crucial 25- to 54-year-old demographic.

Clinton has done interviews with cable news hosts who have fewer viewers, like CNN's Anderson Cooper and MSNBC's Rachel Maddow.

SEE MORE: It Turns Out Donald Trump Did Have Audio Issues At The Debate

The other issue Kelly apparently has — based on her tweet — is she feels Clinton has used her to attack Donald Trump. Perhaps she's referring to this moment back in April.

"His attitude about and what he has said about so many women, the way he treated Megyn Kelly, who is a superb journalist, right? I just don't understand what he thinks is the role of somebody running for president," Clinton told "The View" co-hosts.

Clinton's press secretary told Kelly on Monday it's "only a matter of time" before Clinton comes on her show.