Cage bought the fossil for $276,000 at an auction in 2007. According to federal prosecutors in New York, it had been removed illegally from Mongolia before Cage bought it.
Mongolia bans the export of fossils and other artifacts of scientific or cultural importance.
The fossil is a rare form of Tyrannosaurus called bataar, which is only found in the Gobi Desert.
On Tuesday, a representative for Cage confirmed the actor had bought the skull and received a certificate of authenticity.
“NC fully cooperated with the investigation, including arranging for an inspection of the fossil by agents of the Department of Homeland Security and U.S. Attorney’s Office,” said Cage’s spokeswoman.
Cage agreed to turn it over to U.S. officials for its return to Mongolia, his rep said.
The feds determined that the skull had been shipped from Japan to Gainesville, Florida, in 2006, and was labeled as “fossil stone pieces.”
Cage’s Hollywood resume includes his breakout film “Raising Arizona,” the “National Treasure” series from Disney (DIS) and his Oscar-winning performance in “Leaving Las Vegas.” He has a net worth of $25 million, though he used to be worth much more, according Celebrity Net Worth.
He bought the Tyrannosaurus skull during a time a when he also bought 15 mansions, two castles, four yachts and nine Rolls Royces.
He has since lost some of those homes to foreclosure.