The world continues to rotate on its axis and The Hills co-stars Heidi Montag and Lauren "L.C." Conrad continue to battle as former BFFs.

The Hills' second season finale ended with Montag moving out of the apartment she shared with Conrad to instead live with Spencer Pratt, whom she recently became engaged to.

"Spencer has never felt so incredibly in love in all his life and Heidi feels like she is walking on clouds," an "insider" told In Touch Weekly in the magazine's June 11 issue.  "Spencer wanted to show Heidi his commitment by taking their relationship to the next level."

While Montag and Pratt may be happily engaged, their relationship has apparently disrupted her friendship with Conrad as Montag reportedly declined to attend The Hills: Finale After Party at MTV Studios in New York City because Pratt was not invited.  But Conrad apparently repaid the favor, as Montag and Pratt threw an engagement party for themselves at their Pacific Palisades, CA home on May 25, according to In Touch, with Conrad deciding to not attend despite being invited.

"Lauren was supposed to come but didn't shop up," a "friend" told In Touch.  "Lauren doesn't seem very happy for Heidi and Spencer.  It's like she's jealous because she always wanted to get married young."

With The Hills' third season scheduled to premiere in August, Us Weekly reported in its June 18 issue that Montag has apparently been trying to get some face time on MTV by "crashing" Conrad's scenes.

"Heidi's been showing up at shoot's uninvited," a "source" told Us.  "She knows her best chance for airtime next season is to be in sequences with Lauren."

Their feud was apparently on full display on May 30 at Los Angeles' Les Deux when Montag "ambushed" Conrad.

"Lauren was screaming, 'You're pathetic!'" an "eyewitness" to the drama told Us.  "Lauren was using her hands wildly, saying she didn't want to deal with Heidi."

Montag still wants Conrad to serve as one of her bridesmaids, according to In Touch, however that apparently doesn't translate into chasing her all over town to ask.

"Heidi's recording her album," Montag's representative tells Us.  "She doesn't have time to chase Lauren."