DETROIT -

Actress Lisa Robin Kelly, best known for her role as Lori Forman on "That '70s Show," died on Wednesday at the age of 43.

According to TMZ, Kelly had been staying at a rehab facility in California when she passed away in her sleep. Kelly's agent told TMZ that she had voluntarily checked herself into treatment during the past week.

"I spoke to her on Monday and she was hopeful and confident, looking forward to putting this part of her life behind her," Kelly's agent, Craig Wyckoff, told People. "Last night she lost the battle. Cause of death has not been issued yet and no death certificate has been issued either." 

Kelly had been arrested several times over the last few years for a string of incidents, including DUI, and assault.