Macaulay Culkin left his reclusive life in New York to attend Natalie Portman's California wedding Saturday night.
They've been "friends for years," a source told Us Weekly.
As RadarOnline.com reported, Portman and Benjamin Millepied married near Big Sur with just family and close friends in attendance.
Culkin's presence at the intimate ceremony comes on the heels of a National Enquirer story alleging that the former actor is a heroin addict.
His rep responded to the blockbuster story, calling it "not only categorically without merit, but it is also impossibly and ridiculously fictitious."
Culkin's super-thin appearance has had fans concerned about the Home Alone star for months though.
Macaulay had an eight-year long romance with Portman's Black Swan costar Mila Kunis that ended in late 2010. He has only rarely been seen in public since their break-up.