The season three finale of “The Hills” airs Monday on MTV and Lauren (LC) Conrad reveals that she makes a “life-changing” decision.

Lauren Conrad told People magazine, “I gotta be honest, I haven’t seen the final episode yet. I know that something happens in our lives, but I don’t know what they’re showing. … Something very exciting happens in my life. I can’t tell you what, obviously, because it has to air, but it was a life-changing something.”

So, what’s the big decision on “The Hills” finale?

Asked if it has to do with Brody Jenner, LC comments, “I mean, a little bit, but mostly do to with me. I have to make a very big decision—which I made, which I’m very happy with now.”

We’re on pins and needles. “The Hills” finale airs December 10 on MTV.