Bret Baier joined Bill Hemmer this morning to preview tonight's much anticipated live interview with Hillary Clinton. The 30-minute sit-down will begin at 6:45p ET, with Bret and Greta Van Susteren splitting the questions evenly.

Baier said to prepare, he has read 623 pages of the former secretary of state's new book, "Hard Choices," as well as watched her previous interviews with other outlets.

He said there are other topics that need to be explored and some follow-ups to pursue from the recent interviews.

Howard Kurtz, host of Media Buzz, said the challenge is for Bret and Greta to "prod" Clinton beyond the scripted answers she has already given on subjects like Benghazi. He also said it's interesting that Hillary Clinton has agreed to engage on Fox News given "her wariness with the media in general" going back to her early days as First Lady.

Watch the interview, and make sure to tune in at 6:45p ET tonight for the big interview.