That 70's Show Actress Lisa Robin Kelly Dies

So tragic!

That 70's Show actress Lisa Robin Kelly died in her sleep Wednesday night in Los Angeles, her rep confirms.

"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," agent Craig Wyckoff said in a statement to People.

"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," he added.

The 43-year-old played the older sister to Topher Grace on the Fox sitcom for five years. Kelly was outspoken about her addiction issues and had been arrested at least four times over the past three years for alcohol-related offenses.