Former Fox News host Bill O’Reilly announced on Twitter today that he will appear on his former colleague Sean Hannity’s radio show this afternoon, marking their fourth appearance together in less than three weeks. The conservative commentators -- who famously hated each other until recently -- both seem to think they benefit from this budding collaboration, but the big loser is Fox News, which is stepping on its own efforts to claim that it has moved past the culture of sexual harassment that has tarnished the network’s reputation.

O’Reilly wrote on Twitter today that he would be appearing on Hannity’s radio show to discuss the “Vegas massacre” and the sales of his new book. Bereft of a media home other than his podcast after Fox fired him to resolve the firestorm caused by the revelation that he is a sexual predator, O’Reilly needs these appearances to bolster his sales. The former Fox host typically used his show to plug his books on a nightly basis, and his sales have suffered without that promotional engine.

The appearances with Hannity also give O’Reilly a sympathetic ear as he tries to rebuild his reputation by attacking the women who reported him for sexual harassment and blaming Media Matters -- “the most dangerous organization in America” -- for his firing.

Hannity wants his audience to hear that message as a warning that if they don’t support him amid an ongoing advertiser boycott, he will be forced out at Fox just like O’Reilly.

Fox heavily promoted O’Reilly’s appearance on Hannity’s Fox program last Tuesday, running on-screen graphics about the interview or promotional commercials during every hour of programming from 6 a.m. to 6 p.m. EST. That makes sense as a short-term ratings grab as Hannity moved from a 10 p.m. time slot into a head-to-head fight with MSNBC’s Rachel Maddow.

But in the long run, it’s a disaster for Fox and its advertisers. The network is trying to clean up its reputation after more than a year of terrible headlines and an advertiser exodus caused by its culture of sexual harassment. Fox executives have moved more quickly when such allegations hit the papers then they have in the past, and their PR flacks are writing press releases trumpeting the prominence of the network’s female talent. O’Reilly’s return to their airwaves and his constant association with Fox’s best-known host is a constant reminder that when push came to shove, the network preferred to pay off its former star’s accusers rather than confront him. As I noted last week:

The move gives ad buyers who were already concerned that Fox couldn’t control Hannity a new reason for alarm. It gives advertisers who previously abandoned O’Reilly’s show a reason to fear that their ads elsewhere on the network could end up promoting him. And it gives British regulators -- who were already reviewing Fox as part of Rupert Murdoch’s $15 billion bid to purchase Sky -- a reason to worry about the network’s corporate governance and commitment to changing its seedy culture.

Hannity knows this, too, and he’s all but thumbing his nose at the forces inside Fox who want to change its  reputation. His message is the same one he’s been sending for the past few months, as he openly wars with the network that pays his checks: Fox needs him more than he needs the network.