Kristin Cavallari and Lauren Conrad Hash It Out on 'Laguna Beach' Reunion

Kristin Cavallari and Lauren Conrad are coming clean after all these years.

The "Laguna Beach" stars famously feuded on the hit MTV reality show -- often over the attention of costar and classmate Stephen Colletti ... and they're finally hashing it out.

On Tuesday, the Roku Channel released a trailer for the show's upcoming reunion ... which will be the first-ever time LC and Kristin discuss the drama with cameras rolling!

In one clip of the two of them sitting on the beach, Kristin says ... "We have never had a conversation on camera just the two of us. Are you ready?"

Lauren responds, "No."

For the special -- hosted by actress Casey Wilson -- Lauren, Kristin and Stephen will reunite with Trey Phillips, Talan Torriero, Christina Schuller, Lo Bosworth, Dieter Schmitz, Jessica Smith, Alex Hooser, and Morgan Olsen to get everything out in the open.

The promo shows Kristin recalling some peak points in her feud with LC, saying ... "They said, 'Who do you think is going to be prom queen?' And I said, 'I don't know and I don't care as long as it's not Lauren Conrad.'"

Lauren noted the feeling was mutual, adding ... "We did not like each other."

In the clip, Kristin explains that it took so long to get the gang back together because it was "hard to revisit," but "it just feels like the right time now."