The Simpson sister's were accompanied by their husbands and were spotted sipping wine and cocktails throughout the event. An onlooker told People:
"Ashlee and Evan [Ross] acted like newlyweds. They were cuddled up together in a booth, laughing and showing off cute PDA. Jessica looked really happy to be hanging out with them and seemed to get along great with Evan. Eric [Johnson] and Jessica did their own thing at the party and would check in on each other every now and then. He came over to introduce himself to her friends a few times and would run close to the stage to take photos of the performances."
As for the returningVoice judge, she pushed through her sickness to support Perry:
"Her fiancé [Matt Rutler] held her hand on the way up. She said she was getting over the flu but wanted to come and support Linda."
Watch Miz Aguilera's stunning performance (below)!
Only a day after the Million Reasons singer revealed her battle with PTSD, the A-lister once again opened up about her life with the mental illness -- only this time in a letter for her Born This Way Foundation's website.