Hayden Panettiere Celebrates 21st in Ann Arbor

Ringing in a momentous milestone in her life, Hayden Panettiere celebrated her 21st birthday in Ann Arbor, Michigan over the past weekend.

Becoming a legal drinker on August 21st, the former "Heroes" hottie was joined by her "Scream 4" castmates for a fete held at the Cavern Club.

According to a party insider, the festive soiree included a fireworks display gone awry along with a cute dolphin cake to tribute Hayden's marine life loving nature.

Hosted by David Arquette, fellow partygoers imbibing on the Ann Arbor nightlife included Neve Campbell and Emma Roberts.