Hayden Panettiere's Madhouse Birthday Bash

Hayden Panettiere celebrates her 21st birthday on Saturday (August 21) at the Cavern Club in Ann Arbor, Michigan.

The actress has been in town shooting Scream 4 and celebrated with her brother Jansen and her castmates Adam Brody, Emma Roberts, Neve Campbell and Anthony Anderson.

Beacher’s Madhouse creator Jeff Beacher and David Arquette threw the four-story circus and had the entire cast of their show flown out from the Roosevelt Hotel — Oompa Loompas, burlesque dancers, stilt walkers, fire breathers, acrobats, and 7-foot tall chickens and sheep. Crazy!!!

A “Happy Birthday Hayden” fireworks display went off as the local fire department paraded up and down the block. The Mayor of Ann Arbor John Hieftje also gave Hayden the key to city for her charity work. What a birthday!!!

FYI: Hayden‘s boyfriend Wladimir Klitschko was unable to attend — he’s been at training camp in preparation for his September 11th fight against Nigeria’s Samuel Peter in Frankfurt, Germany.

15+ pictures inside of Hayden Panettiere‘s Madhouse birthday bash…