That '70s Show star Lisa Robin Kelly has died at the age of 43. After struggling with addiction, the actress had checked into rehab again just last week before passing away on Aug. 14. Her rep told People, "Unfortunately Lisa Robin Kelly passed away last evening. Lisa had voluntarily checked herself into a treatment facility early this week where she was battling the addiction problems that have plagued her these past few years. I spoke to her on Monday and she was hopeful and confident, looking forward to putting this part of her life behind her. Last night, she lost the battle. Cause of death has not been issued yet and no death certificate has been issued either."