Manager Craig Wyckoff says Kelly died on Wednesday at a Los Angeles addiction treatment facility she had entered early this week.
No official cause of death was disclosed.
Kelly portrayed Laurie Forman, sister of Topher Grace's lead character Eric, on the Fox series. It concluded in 2006.
Unlike some of her co-stars - Grace, Ashton Kutcher and Laura Prepon - Kelly fell out of the spotlight after appearing on the sitcom until she started making headlines for personal troubles.
She was arrested in November along with husband Robert Joseph Gilliam in connection with a disturbance at their home in North Carolina.
In June, she was arrested on suspicion of drunken driving after her car stalled in California.
TMZ has further details about her death - watch here:
24.com publishes all comments posted on articles provided that they adhere to our Comments Policy. Should you wish to report a comment for editorial review, please do so by clicking the 'Report Comment' button to the right of each comment.
E! Entertainment (DStv 124) will be celebrating the life of Joan Rivers with a special 90 minute Fashion Police programme. Read More »
Fans of Africa’s biggest reality show, Big Brother Africa, will no longer have to wait in anticipation until the launch on 5 October 2014 to meet the Big Brother hotshots. Read More »
A candid quickie!
The aKING frontman!
The Top 3 couples!
The Top 12!
He's back on TV!
Mother City rockers!
The rugby dancer!
A device that converts nose breaths into speech will open new doors for people with Parkinson’s or motor neuron disease.
Cape TownPeoplefinder Career Placements
Cape TownPersona Staff
HousesR 3 595 000
HousesR 3 500 000
HousesR 6 300 000