Kelly's agent says in a statement that 'cause of death has not been issued yet and no death certificate has been issued either.'
Actress Lisa Robin Kelly, who played Laurie on FOX's sitcom "That '70s Show", has died. She was 43. The actress apparently passed away in her sleep on Wednesday night, August 14.
"Unfortunately Lisa Robin Kelly passed away last evening," her agent Craig Wyckoff told PEOPLE on Thursday. "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," he added.
"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," Wyckoff said of the actress.
Danny Masterson, who took part on the show as Steven Hyde, mourned the actress' passing on Twitter. "Terrible, awful news. Brilliant on 70s.... See u next time LRK, kisses," he wrote.
Kelly is mostly remembered for her role as the older sister of Topher Grace's character Eric Forman on the hit show. She left the show after five years. The actress started having problem with alcohol following a miscarriage in 2003. She opened up about her alcohol addiction in an interview with ABC News in 2012, saying, "I had lost a baby. As a result of that I lost everything and I was abusing alcohol."
In recent years, Kelly made headlines because of her legal troubles. Last November, Kelly and her husband Robert Joseph Gilliam were arrested after the police received a report of domestic disturbance. She was arrested in June on the suspicion of driving under influence.