James Cromwell has been arrested for disrupting a University of Wisconsin Board of Regents meeting where he was protesting over animal testing.
University police Sergeant Brent Gruber said the 73-year-old Babe star was fined for disorderly conduct and he and an animal rights activist arrested with him were then released.
The pair held two large signs showing a cat with metal implanted in its head at a UW-Madison lab, while shouting about the treatment of cats.
The director of the school's Research Animal Resources Centre said federal agriculture officials have found their claims to be false.
James was nominated for an Oscar for the 1995 film Babe. Other credits include LA Confidential, The Green Mile and The Artist.