Stars of hit U.S. sitcom That '70S Show have paid tribute to Lisa Robin Kelly, who died on Wednesday (14Aug13) after a long battle with alcohol addiction.

The 43-year-old actress is believed to have suffered a fatal cardiac arrest at a rehab facility in California, just two days after she admitted herself to the clinic in a bid to tackle her long-running alcoholism.

Kelly's former colleagues have now spoken out to pay their respects to the star, who played Laurie Foreman in the show.

Kurtwood Smith, who played her onscreen father Red in the popular comedy, released a statement, which reads, "I am so sorry to hear about Lisa's passing away. I know the last 10 years have been such a difficult struggle for her but I will always remember the lovely, funny and very talented young lady I worked with."

Danny Masterson, who portrayed Steven Hyde on the series, took to Twitter to write, "Terrible, awful news. Brilliant on 70s.... See u (sic) next time Lrk, kisses. Rip Lisa Robin Kelly aka Laurie Foreman."

Former child star MACkenzie Phillips, who has battled her own addiction demons in the past, also paid tribute, insisting she saw comparisons between herself and Kelly.

She tweeted: "Rest in Peace Lisa Robin Kelly. So so sad I didn't know Lisa, but in a way, she is me. And I am her. There is a solution."

Motley Crue star Nikki Sixx has also offered his condolences online, tweeting about the evils of alcohol abuse: "Rip. Sadly actress Lisa Robin Kelly has passed away after a major battle w/ (with) alcoholism.This disease is a evil monster. Aa (Alcoholics Anonymous). Sobriety."