https://www.grunge.com/1096897/bill-maher-facts-about-the-comedian-and-talk-show-host/
One of the comedian's frequent guests on his show is the right-wing pundit Ann Coulter. Maher refuses to heed the haters like usual and will have whoever he wants on "Real Time," but Coulter is a special case because their relationship goes beyond being simply colleagues as political commentators who are on opposite ends of the spectrum. Regardless of their differences, the two are close friends.
On top of their on-screen appearances together, both have separately defended the other. When Coulter was on "Hannity" and the host was critical of Maher, she responded, "I obviously don't agree with his politics. I like him. He's a true and loyal friend, he always has been, and he bought me dinner. So, I'm not going to say anything bad about him ... I'm easy. I'm a cheap date" (via Mediaite).
Likewise, Maher was asked by Variety why he has Coulter on his show, and he said, "She's not stupid. I don't exactly read her books. But I know from when we've covered her issues in the past, it's not like she doesn't do research."