'Hills' Buzz Moment #4: Heidi Moves Out ... And On

When Heidi moved in with Spencer, her friendship with LC forever changed.

Over the course of the five seasons Lauren Conrad was on "The Hills," there was no shortage of drama between LC and onetime pal Heidi Montag. Back in the day, these two girls weren't just best friends, they were also roommates. With the show's final season kicking off Tuesday, there was one moment that became the turning point in their friendship — and it comes in at #4 on our list of the most buzzed-about "Hills" moments.

In the first episode of season one, fans could see that LC and Heidi were two very different girls, but it was also evident that they had each other's backs. Over time, the two ladies' opinions would really differ when it came to a guy named Spencer Pratt. "He's not a good person," LC told Montag about her now-husband. "I'm telling you that because I'm your friend."

It wasn't until Heidi decided to move in with Spencer that things really started to heat up. Even though her friendship with Lauren was already on the brink, Heidi was convinced they could make it work. LC realized at the time that Heidi's exit would be the end of their friendship, but like any good pal, she told her, "You know you can always come back."

'The Hills' Most Buzzed-About Moments

- #5: Kristin Cavallari Declares War

- #6: Heidi And Spencer's Many Weddings

- #7: Holly Gets Tipsy At Speidi's Rehearsal Dinner

- #8: Heidi Montag Crashes Lauren's Party

- #9: Justin Is Renamed 'Justin Bobby'

- #10: Stephanie Pratt's Job Interview

In the end, LC was right. Heidi drove off in a moving truck, leaving Lauren and their friendship behind. And even though LC would make a cameo at Speidi's wedding, the friendship between the two girls never really had the magic it once did. What was Spencer's take on the whole thing? "You won't regret this, I promise you," he told Heidi as they drove off into their future together.

What are some of your favorite "Hills" moments? Let us know in the comments below!

"The Hills: Final Season" premieres Tuesday at 10 p.m. ET/PT followed by "The City" at 10:30 p.m. ET/PT on MTV.