The Hills stars know they need to get along sometimes...

One of these times is if an The Hills girls' cover shoot was the first time the four girls spent any time together in the last two years and sources say there was a lot of tension on the set.

Spencer, Heidi's boyfriend did not go to the shoot - this might have helped as he is one of the reasons Heidi and Lauren - who were best friends forever before - ended their friendship.

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