Kelly had been staying at a rehab facility in California when she passed away in her sleep, according to TMZ.
Kelly's agent told the gossip site that the actress had voluntarily checked herself into treatment during the past week.
"I spoke to her on Monday and she was hopeful and confident, looking forward to putting this part of her life behind her," Kelly's agent, Craig Wyckoff, told People. "Last night she lost the battle. Cause of death has not been issued yet and no death certificate has been issued either."
In 1996 Kelly appeared on 26 episodes of DAYS OF OUR LIVES as Jill Stevens.
Kelly had been arrested several times in the past three years for a string of incidents. In 2010, Kelly pled guilty to misdemeanor drunk driving, earning her a night in jail and a year of unsupervised probation. In March 2012, Kelly was arrested on a count of spousal abuse, though charges were later dropped. In November of the same year, Kelly and her husband Gilliam were both arrested for assault. In June of this year, the actress was arrested again on suspicion of driving under the influence.
In June Kelly had filed for divorce from Gilliam, citing irreconcilable differences for as the cause of their split.
Check out a clip of Lisa Robin Kelly on DAYS OF OUR LIVES below: