The Lost Boys actor Corey Haim was a "tormented soul", friend and fellow actor Corey Feldman has said.
Paying tribute to the star, Feldman said he wept when he heard Haim had died at a California hospital on Wednesday aged 38.
"This is a tragic loss of a wonderful, beautiful, tormented soul, who will always be my brother, family, and best friend," he said in a statement.
A post-mortem is due to be held to determine the cause of death.
Troy Searer, an executive producer of the short lived reality show The Two Coreys starring Haim and Feldman, said Haim's "heart and his potential were only outmatched by his demons".
The assistant chief of the Los Angeles County coroner's office, told local television reporters Haim had been suffering flu-like symptoms.
Ed Winter said Haim's mother, who lived with the actor, called paramedics after he collapsed while getting out of bed at his apartment. He later died at Providence St Joseph Medical Center.
Winter added coroners found some prescription medication in Haim's apartment but "no illicit drugs".
After battling drug abuse for years, Haim openly talked about overcoming his addictions around the time he was promoting his reality TV series in 2006, saying he had become clean and sober.
The Canadian-born star's first role was in the 1984 film Firstborn and came to prominence in the 1986 movie Lucas alongside Charlie Sheen and Winona Ryder.
The star told The Sun in 1994 it was while filming The Lost Boys opposite Kiefer Sutherland in 1987 he discovered drugs.
He admitted his drug habit damaged his career and the star later went into rehab and was put on prescription drugs.
However his career outlook had been improving in recent months - the actor appeared in Crank 2: High Voltage last year and had been promoting his latest film, American Sunset.