Former WWE superstar Joan Marie Laurer, also known as Chyna, has died at the age of 45, her manager said in a statement on Twitter early Thursday.

The immediate cause of death was unknown. The Los Angeles County Department of Medical Examiner-Coroner told FOX411 she was found dead in her Redondo Beach, Calif., home on Wednesday afternoon.

"The last contact she had with somebody was Sunday evening," Assistant Chief Ed Winter told us Thursday. "She was discovered unresponsive yesterday afternoon so we don’t know when she passed away. We don’t have a timeline yet to figure out was it Sunday night or Monday night or [at another point]."

Her manager told Pro Wrestling Sheet she had been taking medication for anxiety and sleep deprivation. The coroner's office is investigating if her death could have been an accidental overdose. Still, the office has not ruled anything out. 

"It was reported as a possible overdose or an accidental overdose or as natural causes. I understand that she evidently had a history of drug use so we’re looking at everything," Winter explained.  

In a bizarre video posted on her YouTube channel on Sunday, Chyna was seen with smudged makeup, drinking water and juice. The star made a smoothie during the 13-minute video and wore feathers as she took the camera around her home and rambled to fans. 

“She will live forever in the memories of her millions of fans and all of us that loved her,” a statement read on her Twitter account.

WWE Chief Brand Officer Stephanie McMahon paid tribute in a Tweet calling Laurer's death "tragic news" and describing Chyna as "truly a pioneer in our industry".

"I knew Chyna before she got into wrestling.  She was a kind, good hearted person," former wrestler Hulk Hogan told FoxNews.com.

Laurer, a native of Rochester, New York, was mostly known for performing under the name Chyna during her career with WWE (then known as WWF). She was also a renowned body builder and an adult film star.

In 1999, Laurer became the first woman to participate in the WWF’s Royal Rumble event. Later that year she broke another barrier by becoming the first woman to participate in the King of The Ring tournament — which had mostly been dominated by male performers — and shared a championship belt.

After issues with WWE, Laurer and the company parted ways in 2001.

She left the wrestling business altogether in 2011 after stops at New Japan Pro Wrestling and Total Nonstop Action Wrestling.

In between her wrestling career, Laurer started in six adult films and was featured on four seasons of “The Surreal Life,” “My Fair Brady” and “Celebrity Rehab with Dr. Drew” on VH1.

Ultimately, Laurer struggled with substance abuse. Former boyfriend and wrestler Sean Waltman told the Calgary Sun in 2005 that she was battling drug and alcohol-related issues as well as a mental illness.

After a reported domestic abuse incident involving Waltman in that same year, the New York Post reported that she had stripped naked and jumped into a fish tank at a New York nightclub. Later, during an appearance on the Howard Stern Show, she reportedly was slurring her words and didn’t deny wanting to do cocaine if it was placed in front of her.

Laurer appeared on “Celebrity Rehab with Dr. Drew” in 2008, but claimed that she wasn’t an addict. She also said she had a bad relationship with all of her family members, including her siblings.

In 2008, Laurer was rushed to the hospital after her birthday party because she was found passed out with cuts on her arms. Two years later, she was hospitalized after overdosing on pain medications.

In February of 2015, Laurer disclosed she had reconciled with her mother and that her father had died in 2014.

The investigation into Laurer's death is ongoing and the coroner's office told FOX411 an autopsy will be done in the coming days. The final results of the investigation could "take up to several months," the coroner's office said. 

Fox News' Leora Arnowitz contributed to this report.