Bunny Beef! Holly Madison's Bitter Feud With Kendra Wilkinson

Holly Madison is hopping mad at her former Girls Next Door co-star, Kendra Wilkinson, calling her the "fakest person I've ever met."

Related: Holly Madison Contemplated Suicide at Playboy Mansion

While the blondes appeared friendly on their E! reality series about life with Playboy founder Hugh Hefner — and after — appearances are deceiving, Madison says in her new book, Down the Rabbit Hole: Curious Adventures and Cautionary Tales of a Former Playboy Bunny. The ladies only played nice for the cameras and severed ties completely when the show went off the air after five seasons in 2010.

Madison, who was Hef's No. 1 girlfriend, said things were rocky with Wilkinson from the start. Six years her junior, Wilkinson, who was only 19 when she moved into the mansion, had a "hustler mentality" and "sense of entitlement," Madison wrote in her book, according to People magazine. The San Diego native — who was a wild child, using cocaine at just 13 – lied to Hef and told him she was a college student because he didn't like strippers. Wilkinson also ticked off Madison and the other girls by boldly requesting the "really big room" when she moved into the Playboy Mansion. That apparently was a big no-no.

"Despite my attempts to befriend Kendra, she continued to push me away," Madison wrote, according to E! News. "Hungry from her own 'team,' Kendra desperately tried to make each new Playmate who arrived at the mansion her friend — and her friend alone."

Rainbow's mom called out Kendra for telling lies about life in the Playboy mansion.

"In Kendra's book Sliding into Home, she describes Hef asking her to be a girlfriend and handing her a house key before he invited her up to the bedroom," Madison wrote. "Now, I don't know if Kendra is trying to sound extra-desirable, innocent, or if her memory is just super rusty, but of course that's not how it really went down. Hef isn't stupid. He never asked anyone to become a girlfriend before they joined him in bed. And he never made a habit of carrying around extra sets of room keys."

But things came to a head after Wilkinson departed the show to marry Hank Baskett. Madison, who tied the knot with Pasquale Rotella in 2013, was "hurt and confused" when the Kendra on Top star told a magazine that she was no longer friends with her or fellow girlfriend Bridget Marquardt.

"Kendra had apparently given an interview to a tabloid explaining that she wasn't friends with either of us as if she were somehow better than everyone else," Madison wrote. "Of course I wasn't going to stoop to her level and address this only on social media, so I decided to text her how I truly felt: that she was a coward and that she tried to act like the 'real' girl on TV, but she's the fakest person I've ever met — and that if she had a problem with me, she should have confronted me like an adult instead of just going silent."

Wilkinson didn't let Madison's text go unanswered. Her reply? "WHO ARE YOU???? I DON'T EVEN KNOW YOU! WE WERE NEVER FRIENDS. IT WAS ALL JUST WORK," Madison wrote.

After that? Madison "deleted her number from my phone. Kendra and I haven't spoken since, and I have to say, I don't miss her."

It sounds like Madison's relationship with Hefner is just as frosty. She said she hasn't talked to her ex, who married Crystal Harris in 2012, in four years. And after he reads her book, which is out on June 23, it's not going to inspire any tearful reunions.