03/21/2012 AT 08:00 PM EDT
Kaley Cuoco isn't moping around following her split
from ex-fiancé Josh Resnik.
In fact, the Big Bang Theory
star, 26, may have already moved on to a new beau.
The actress headed out to Bardot nightclub in Hollywood on St. Patrick's Day, where she and a mystery man spent the evening attached at the hip, celebrating her Zooey
magazine cover at a Cellairis-sponsored party.
"Kaley and the guy were giggling all night in the V.I.P. section, where they were kissing, dancing and even did an impromptu photo shoot, making funny faces together," an onlooker tells PEOPLE. "Kaley seemed like she was truly having a good time and was completely being herself."
Adding that the evening seemed "light and casual" for the starlet – who was "beaming" in a yellow ensemble throughout the night – the source says, "She looked like she was just out to have a good time."
Cuoco, whose engagement was announced
in October, broke the news of her split at an event earlier this month.
A rep for Cuoco has no comment.