Heidi Montag and Spencer Pratt scheme their way into the glossies

There's some nastiness brewing in "The Hills." MTV's sequel to the hit "reality" show "Laguna Beach" follows Lauren Conrad as she goes to fashion school and interns at Teen Vogue.

But things have been icy between Lauren and her former BFF Heidi Montag because of Heidi's scheming boyfriend (now fiancé) Spencer Pratt. At the end of season 2, Heidi had moved in with Spencer and apparently lost Lauren's friendship as a result. But fame-hungry Heidi is determined not to lose screen time as well.

According to Us Weekly, Heidi is so desperate to be featured in season 3 of "The Hills" that she is encroaching on Lauren's scenes. Says a source, "Heidi's been showing up at shoots uninvited. She knows her best chance for airtime next season is to be in sequences with Lauren."

On May 30, Conrad hit the roof. While at Les Deux with Montag and Pratt, she confronted her frenemy about her scene-crashing antics. One onlooker told Us, "Lauren was screaming, 'You're pathetic! Lauren was using her hands wildly, saying she didn't want to deal with Heidi."

It looks like Heidi's attempts to become a bold faced name haven't stopped there. Celebrity Babylon is reporting that her engagement to Spencer is a publicity stunt created to generate more interest in the couple. An MTV source told CB, "It's an arrangement that suits both of them. They won't be walking down the aisle, they will go through the motions of planning a wedding, and then have a big break-up that will get lots of press. All caught on camera by photographers, of course."