Heidi Montag's 21st Birthday Celebration

Taking a break from the drama of The Hills, Heidi Montag celebrated her 21st birthday in Las Vegas last night.

According to club-goers on the scene, "Heidi and Spencer were in a very festive mood at LAX, downing Veuve Clicquot and passing out flutes to random people in the crowd."

Another highlight from the evening occurred when Heidi took to the stage and performed her new single, "Higher."

Meanwhile, in a recent interview, Heidi got a little vocal over her displeasure of the preferential treatment Lauren Conrad receives from MTV producers.

Montag told CosmoGirl, "I just have to accept that Lauren will never be seen in a bad light."

"They (the producers) don't show the footage of how Lauren was sort of obsessed with (fiancé Spencer Pratt), or how she called my mom in Colorado and told her I was involved in an abusive relationship, or how she would scream at me in the middle of the club if I wanted to leave... to go see Spencer."

Gossip Girls

To watch Heidi sing at her birthday party - Click Here!

Enjoy the pictures of Heidi's Club LAX birthday party in Las Vegas (September 17).