Heidi Montag is not over what went down on "The Hills" -- but she's trying.

In an effort to mend their marriage, Montag and husband Spencer Pratt have joined WE's "Marriage Boot Camp: Reality Stars," but the blonde reality star has another relationship to fix first.

During a therapy session, the 28-year-old reality star breaks down talking about her former friendship with Conrad, and the fight that tore them apart eight years ago. It was implied in the MTV reality show that Pratt had made up a story that L.C. had made a sex tape with her then boyfriend Jason Wahler. When Montag was confronted with this claim, there was a drunken meltdown scene outside a L.A. nightclub that will go down in "Hills" history.

From then on, the girls were frenemies. "I was the best friend you've ever had," Montag said as if L.C. was in the room with her. "Lauren, I forgive you for being so insecure in your life and so frustrated for everything that you went through that you felt like you had to blame it on me because that was easier."

Speaking through sobs, she added, "I forgive you for trying to ruin my life."

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But does she fully forgive her former gal pal? "I forgive you for everything. I just don't want to have this with you anymore," Montag continued. "I do love you despite everything you've done for me. I do."

Meanwhile, Conrad doesn't seem phased by her friendship breakup with Montag. Almost never talking about it, the 29-year-old has since become a lifestyle guru, started her own Kohl's clothing line, authored several books and most recently became a newlywed.