Lisa Robin Kelly, who played Eric Forman's older sister Laurie for two seasons on "That '70s Show," died Wednesday at age 43, her agent Craig Wyckoff said Thursday.

"Unfortunately, Lisa Robin Kelly passed away last evening," Wyckoff said in a statement. "Lisa had voluntarily checked herself into a treatment faciility 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."

Wyckoff said that no cause of death had yet been determined.

Kelly played Laurie for the Fox comedy's first two seasons, then left the show for two years, returning for occasional appearances during the fifth season. The role was recast with another actress for the sixth season.

She told ABC News that she lost a baby during her time on the show and as a result, " I lost everything and I was abusing alcohol."

Kelly had been in the news recently for various encounters with the law. In June, she was charged with parking on an active freeway near Burbank, Calif. She pled guilty to DUI in 2010 in North Carolina. In March of 2012, she was arrested on a felony charge of corporal injury upon a spouse and released on bail. The L.A. County district attorney declined to file charges in that case.

In November 2012, Kelly and her husband were both arrested for assault after a disturbance at their North Carolina home. They were later released on bond.

Kelly majored in acting at Chicago's DePaul University, graduating in 1992. She also appeared on such TV shows as "Married ... with Children," "Murphy Brown," and had small roles in movies, including 1999's "Jawbreaker."