'8 Mile' Actor Nashawn Breedlove Dead at 46

Nashawn Breedlove, famous for battle-rapping Eminem in the movie "8 Mile," is dead.

A family member tells TMZ ... Nashawn died in his sleep Sunday at his home in New Jersey. We're told his loved ones do not yet know the cause of death.

Nashawn played Lotto in the 2002 movie, which is loosely based on Eminem's life ... and he's known for a scene where his character takes on Em's B-Rabbit in a rap battle.

In his movie rap, Nashawn sings ... "I feel bad I gotta murder that dude from 'Leave it to Beaver'" ... and the crowd goes nuts, though he eventually loses the showdown.

Before his big break on '8 Mile' Nashawn was rapping under his stage name OX ... with a feature on the soundtrack for the 2001 movie "The Wash" with Dr. Dre and Snoop Dogg.

Rapper Mickey Factz was first to report Nashawn's death, remembering him for his "tenacity and aggressiveness" as a battle rapper.

Nashawn was 46.