Sean Young was placed under citizen's arrest after a fight at the post-Oscars Governor's Ball, Los Angeles police said.
The 52-year-old Blade Runner star was arrested at 9.25pm on Sunday and was booked at the Hollywood police station for investigation of misdemeanour battery.
City News Service said the star - whose movie credits also include Stripes and No Way Out - posted 20,000 dollars bail and was released early on Monday morning.
Police Sgt Enrique Mendoza confirmed the arrest but wouldn't give details about the incident or the alleged victim.
The Governor's Ball is the official Oscar party and is held above the awards show's venue, the Hollywood & Highland Theatre.
SLIDESHOW: Stars arrive for the Governor's Ball