"Some guy jumped over the barricades and made contact with Brad Pitt," Officer Nuria Vanegas of the Los Angeles Police Department said.
There were no immediate details on whether Pitt was injured.
Police identified the suspect as Vitalii Sediuk. The 25-year-old Sediuk was booked on suspicion of misdemeanor battery at the LAPD Hollywood Station shortly after 10 p.m. and was being held in lieu of $20,000 bail, according to online Sheriff's Department booking records.
Investigators were trying Wednesday night to sort out the details of the incident. But the suspect "made enough contact where he was arrested," Vanegas said.