The actress reached the milestone on Aug. 21 and marked the occasion with a spectacular bash on the Detroit, Michigan set of her new movie Scream 4 - complete with fireworks and a three-foot dolphin birthday cake.
But Panettiere wasn't satisfied with the festivities and jetted back to her native New York this weekend so she could enjoy a more low-key birthday bash with old friends.
The star was spotted feasting on tacos and burritos and downing cheap cocktails and shots with eight pals at Mexican restaurant Blockheads in Manhattan on Friday night.
There was one conspicuous absentee - Panettiere's giant boxer beau Wladimir Klitschko. The onlooker adds, "She did look like she was missing her boyfriend. She was on her iPhone every five minutes, checking for messages from him."