Once again, Tucker Carlson has big shoes to fill at Fox News.
It's only been three months since Carlson took over the 9 p.m. ET time slot that opened up after former Fox News anchor Megyn Kelly's departure for NBC, but Carlson is now set to replace yet another TV ratings giant at Fox News. The cable news network said on Wednesday that it is tapping the conservative commentator to replace anchor Bill O'Reilly, who is leaving Fox News after 21 years with the network amid backlash over sexual harassment allegations.
In a press release announcing O'Reilly's immediate departure, Fox News said that Carlson's show, Tucker Carlson Tonight, will be moved up one hour to take over the 8 p.m. ET slot vacated by O'Reilly. Replacing Carlson's program in the 9 p.m. hour will be the The Five, the roundtable news discussion program featuring co-hosts Kimberly Guilfoyle, Dana Perino, Bob Beckel, Greg Gutfeld, Jesse Watters, and Juan Williams. Commentator Sean Hannity's program will continue to follow that time slot at 10 p.m. ET. The changes will take effect Monday, April 24.
Carlson has had no trouble developing a strong following in his short time following The O'Reilly Factor on Fox News, with the former CNN and MSNBC host averaging roughly 3.3 million nightly viewers. Those numbers put Carlson right behind O'Reilly in the ratings race. O'Reilly's show has consistently topped the cable news ratings during his two-decade run at Fox News, and the firebrand conservative anchor had recently averaged nearly 4 million nightly viewers in the first quarter of 2017.
Of course, it is also fair to say that Carlson's show benefitted from having O'Reilly's consistent presence as a ratings lead-in. Only time will tell how Carlson manages to fill the primetime slot and if the loss of the network's biggest star will hurt Fox News ratings overall.
In a statement on Wednesday, Fox News' parent company, 21st Century Fox, said: " After a thorough and careful review of the allegations, the company and Bill O’Reilly have agreed that Bill O’Reilly will not be returning to the Fox News Channel."
Fox News parts ways with O'Reilly in the wake of mass protests calling for the controversial anchor to be fired after a recent report from The New York Times showed that Fox and O'Reilly have paid out $13 million to five women who accused the anchor of sexual harassment. Various other allegations of harassment have also popped up in recent weeks, prompting dozens of major advertisers—including BMW of North America, Allstate, French pharmaceuticals maker Sanofi SA, and several others—to pull their ads from O'Reilly's show.
Get Data Sheet, Fortune's technology newsletter.
Speaking to the press earlier this month, President Donald Trump defended O'Reilly, saying "I don't think Bill did anything wrong."
Fox also brought back corporate law firm Paul Weiss to investigate the claims against O'Reilly. Last year, the law firm conducted an investigation in multiple sexual harassment allegations against Roger Ailes, the former Fox News chairman, which resulted in Ailes' resignation.
O'Reilly abruptly left for an Italian vacation last week, sparking speculation that he may not return to the network. New York magazine's Gabriel Sherman, who wrote a book about Ailes and Fox News, reported earlier this week that 21st Century Fox CEO James Murdoch wanted O'Reilly off the network and that he and his brother, Fox executive co-chairman Lachlan Murdoch, had convinced their father, Rupert Murdoch, to part ways with the longtime Fox News anchor.