Kendra Wilkinson is clearly not abiding by the phrase, "If you don't have anything nice to say, then don't say anything at all."

In a preview clip for an upcoming Kendra on Top episode released by WEtv, Wilkinson was venting to her "partner in crime" Jessica about Holly Madison, who had accused Hugh Hefner a few months ago of offering her drugs, playing mind games and bribing her when she lived in the Playboy mansion.

Wilkinson fired back at Madison for "re-writing history" in defense of Hefner, as both girls had previously starred in The Girls Next Door with each other. Wilkinson had a lot to say behind Madison's back, but she also apparently planned to confront her and throw a copy of Madison's tell-all memoir Down the Rabbit Hole in her face.

"Sign this b-tch," Wilkinson, 30, told her friend in regards to what she'd love to say to Madison, 35, at her book signing.

"Things might get pretty ugly. We left the mansion a long time ago. I would be respectful if she were to tell her own story like I did. But don't bring others down. I can't believe she's getting away with saying stuff and making it seem like it's [factual]. From my perception, what Holly is saying is extremely false. I'm like, 'Where did this sh-t come from?,'" Wilkinson vented.

Wilkinson insisted Madison has been "living as a fake cartoon." But in Madison's book, she said Hefner was controlling and she was constantly trying to follow his rules.

"She's not living on Earth with us," Wilkinson told Jessica while riding in a car in the clip. "And that's how it felt, all those years living [in the mansion with her]. She really played this role -- this fantasy type of role. It wasn't because of Hef. Hef never told her and forced her to do that. Maybe that's why he didn't marry her," she said.

Wilkinson explained Hefner is "too nice of a guy" to have a voice in the matter and she just hates how Madison is getting away with trashing him.

The promo clip then ended on a cliffhanger in which Wilkinson stated, "This is disgusting. I'm not going to let this bitch get away with something like that," as she was about to enter the signing.

Kendra on Top premiered its fourth season in late August.