WWE legend Chyna -- real name Joanie Laurer -- has died ... and officials are investigating as a possible overdose, TMZ Sports has learned.

We've learned she was in her apartment in Redondo Beach, CA ... south of L.A. -- and police got the call around 7:30 PM. Our law enforcement sources say she had not been seen or heard from for a few days. A friend went to check on her yesterday and found her unresponsive in the bedroom of her home and made the call to police.

Officers were on the scene late Wednesday investigating the death as a possible overdose -- due mainly to her history with drugs. Prescription bottles were found in the home, but there were no illegal drugs ... according to our sources.

Cops say there are no signs of foul play.

Chyna was 46 years old.

A statement was posted to Chyna's official Twitter account confirming the death ... saying, "It is with deep sadness to inform you today that we lost a true icon, a real life superhero."

"She will live forever in the memories of her millions of fans and all of us that loved her."

Laurer's manager first confirmed the death to ProWrestlingSheet.com.

She posted a video to her YouTube page earlier this week -- she looked like she was struggling.

Chyna was a game changer during her stint with the WWE -- famously teaming up with Triple H to become one of the original members of D-Generation X. She was also the first woman to enter the Royal Rumble.

Chyna went on to pose for Playboy before transitioning to reality TV. She appeared on "The Surreal Life" in 2005.

Later, Chyna got into porn ... releasing 6 films from 2004 to 2013.

She later went to Japan to teach English.

Chyna struggled with addiction for years -- and appeared on 'Celebrity Rehab' back in 2008.