Audrina Patridge Details Why She and Lauren Conrad 'Aren't Friends' Anymore: 'I Felt So Betrayed'

In her new memoir "Choices," out today, the reality TV star reveals what caused a falling out between the two -- who, aside from a very brief recent run-in, haven't spoken to each other since costarring on the MTV series.

"Unfortunately, one connection that didn’t last was my relationship with Lauren, who doesn’t really talk to anyone from the old cast," writes Audrina in the book. "There are reasons that she and I aren't friends anymore, and there was a lot of turmoil between us that we couldn't talk about on-camera at the time. It's what led to me moving out of the pool house out back when I lived with her and Lo, which might have seemed abrupt on the show, but in reality had been a long time coming."

According to Patridge, she and LC had the same management team and felt that a lot of the opportunities being sent to her were given to Lauren instead. "Yes, I blamed my agents for this, but it still wasn't great for my friendship with Lauren," she explained.

"I also found her to be very controlling over her friends. If you're in her circle, you have to do and say what Lauren does and says. Otherwise, you're on the outs," Patridge continued. "Heidi experienced the same thing. To an extent, I understand wanting to have control, especially in the reality TV world Lauren grew up in, when so much is controlled and decided for you. But there are limits. I (usually) had to do what the producers said—but I sure didn't have to obey Lauren."

Then, there was the Justin Bobby of it all. Audrina had a rollercoaster, on-again-off-again relationship with Justin Bobby Brescia throughout the show -- and, according to Patridge, he may have had a little something going on with Conrad too.

Per Patridge, while LC "acted like she hated Justin while the cameras were filming," it was "a different story" off-camera. "When Justin and I were broken up, Lauren ran into him in Vegas and, according to a good friend of mine, ended up hooking up with him. When I heard this, I felt so betrayed," Patridge continued, pointing to something that did play out on "The Hills" at the time.

"Neither of them would answer my calls or texts until the cameras were rolling. Apparently Lauren was saving her take for the cameras, and when we finally talked, she had it all twisted around to make me sound like I was delusional and out of my mind," wrote Audrina. "Then she got mad at me. Lauren and I were never really friends again."

At the time the rumors first hit, Conrad addressed it on both the show and on her MySpace page -- reportedly saying the accusation was "insulting on so many levels." She added, "I did not and would never hook up with Justin. I'm accused of being a bad friend, a slut and a liar all at once. It would actually be funny if people weren't taking it seriously."

After all that went down, LC left the show and Kristin Cavallari was added into the mix until the series came to an end. According to Audrina, she and LC "haven't talked since" Conrad's exit -- aside from a very brief run-in with their children at a Disney on Ice show.

"We said hello and chatted for a minute before moving on. There was absolutely no drama, and neither of us wanted to revisit the past," she said. "At this point, as grown-ups, we are not friends, but we are friendly if we run into each other. It would be silly to waste time on an old feud when we're with our families and our priorities are so clearly different now."

Audrina's book, "Choices," is available now.