Taylor Swift Had 'Fun All Night' at Mike Hess' Birthday Party!

Taylor Swift makes her way inside her gym to get in a workout on Monday morning (August 8) in New York City.

Over the weekend, the 26-year-old entertainer hit the stage with Nelly to perform for their friend Mike Hess‘ birthday! Be sure to check out the videos if you missed it!

“Taylor was in an amazing mood, and super fun all night. She danced her ass off. At first she didn’t want to perform but then Nelly asked her. Everyone was super into it, the crowd loved it,” an insider told E! News about the performance.