Lindsay Lohan was spotted at Madonna's film screening in New York City until the wee hours of the morning on Tuesday just two months after completing rehab.
The 27-year-old actress served a 90-day court-ordered stay in rehab in order to kick her alcohol and drug use and was released in early September.
Following her recovery, Lohan sat down with Oprah Winfrey and committed to remaining drug-free.
Although her drinking days are over, the actress still attended the party for Madonna's film "Secret Project Revolution" at the Gagosian Gallery in NYC.
"Lindsay came in around 10:30 p.m. and waited the whole time for the film," said an onlooker speaking to Life & Style magazine. "It was supposed to start then, but Madonna showed up an hour late."
As the night went on, Lohan screened the film and stayed on to socialize.
"She was very low-key and relaxed," the eyewitness added. "She said hello to Madonna and other guests throughout the night. Once the party got going, she was dancing- but not drinking."
Anderson Cooper, Calvin Klein and Madonna's ex-husband Sean Penn joined Lohan at the party. See a photo of the celebrities here.
Despite the alcohol at the party, Lohan maintained her sobriety, according to Life & Syle.
"Her friends were drinking around her," the onlooker noted. "They stayed until around 1 a.m."
Many of Lohan's supporters, including Oprah Winfrey, have voiced optimism that the actress' trouble with drugs and alcohol are behind her, and Madonna's party proves they could be right.
Winfrey, who was the first to interview Lohan after the rehab stint, expressed utmost confidence in the starlet.
"I thought that she's in the best place that I've ever seen her," Winfrey said while on "Good Morning America" in July.
Meanwhile, Lohan's mother Dina Lohan is facing legal issues after a DWI charge on Sept. 12. The 51-year-old surrendered her license and pleaded not guilty on Tuesday in Hempstead, New York.