06/30/2011 AT 02:40 PM EDT
has plenty to celebrate now that she's free
to come, go and go out on the town – and she's wasting no time rising to the occasion.
Released early from her house arrest sentence Wednesday, the starlet, 24, got back in the swing of things in her Hollywood stomping grounds later that night.
In her first outing after 35 days of confinement for pleading no contest
to misdemeanor necklace theft, Lohan hit up the hotspot Lexington Social House for a friend's party.
"She was in a good mood," an onlooker tells PEOPLE. "She definitely seemed happy to be free and out celebrating with friends."
Joined by party pals Emile Hirsch and Lyndsy Fonseca, who postponed her celebration for nearly six months so Lohan could attend, Lohan was spotted enjoying her freedom – and a cocktail, according to a source.
Lohan, who is no longer prohibited from consuming alcohol, also nibbled off of her friends' plates before heading out with her posse of 10 in the early morning.
"Of course me going to my best friends going away dinner is a headline," the actress Tweeted
. "Nothing exciting happened aside from the very yummy hummus and pita."
Lohan will remain on probation – stemming from her two DUI cases in 2007 – for the next three years and is due for a progress review on July 21, although she is no longer subject to random drug and alcohol tests.