Daigo Kashino, 33, was stabbed in the abdomen with a 28-inch sword at a rehearsal studio in Taito Ward on Monday, The Japanese Times reported. He died at a Tokyo hospital hours later.
The police have confirmed the weapon was a prop, according to the paper.
Kashino and his fellow actors were reportedly practicing an action sequence at the time of the incident, although no one claimed to witness the actual stabbing, according to the Associated Press.
The other actors allegedly turned around when they heard Kashino growning and noticed he was hunched over and wounded in the stomach, Japanese public broadcaster NHK reported, according to the AP.
An autopsy has been scheduled to determine the exact cause of his death, The Japanese Times reports.