Not all That '70s Show alumni have the happy ending that Mila Kunis & Ashton Kutcher have... such as Lisa Robin Kelly, who tragically died not long ago. Today, however, it has been confirmed that Kelly died of an accidental drug overdose.

According to TMZ.com, Kelly -- who played Eric Forman's older sister on the show -- died on Aug. 15 while in an alcohol rehabilitation facility in Los Angeles. When she was originally autopsied, the coroner couldn't rule a cause of death; the toxicology reports were sent out to confirm what the actress specifically died from. Though the exact drugs found in her system were not revealed, Kelly was hospitalized with a .34 BAC just a few days before she died. For purposes of reference, a BAC of that level will lead to severe central nervous system depression, unconsciousness, loss of bladder function, dysequilibrium, shallowed breathing, decreased heart rate, and yes -- even death.

According to The Daily News, Kelly originally checked into the treatment center on Aug. 12 to "get her life back on track." After ruling out foul play, her death went straight to the Los Angeles County coroner per state law (even though the doctor, at the time, said it was an embolism that killed her). "You can't tell an embolism by looking at a body. If it's true the doctor said that, he or she shouldn't have a medical license," said Kelly's manager, Craig Wycoff. "If some kind of mistake cost her life, we want to know."

Wycoff also said that Kelly didn't have the happy ending that her other co-stars had because she was plagued by personal problems, not the least of which being her addiction. "She later admitted a drinking problem and was arrested multiple times over the last few years for DUI, assault and alleged spousal abuse. "I think people should remember the life lesson that when you do things to excess, there are consequences. Lisa's powers didn't get displayed to their full extent due to her personal problems," Wycoff said to the Daily News.

The coroner's full report is expected to be released in about two weeks.