The 'Beautiful' singer told US Weekly that she was happy to feature on the hit HBO show's seventh season finale because she is a great fan of the series.
"I am a fan of the show, so when I was asked to appear on the finale I was so excited," she said.
Aguilera noted that the highlight of the shoot was being able to work with Jeremy Piven, who plays high-strung Hollywood agent Ari Gold.
She explained: "I loved working with Jeremy. He is hysterical. Who doesn't love Ari Gold?"
Entourage's creator Doug Ellin added that Aguilera was the perfect choice to perform at the surprise party thrown by the super-agent for his wife.
"I thought she was the perfect star to deliver a private performance for Ari Gold," Ellin said. "The song and her persona made for an unforgettable moment"
Entourage will return for an eighth and final season in 2011.