Former Pop Idol star Darius Campbell Danesh died from "inhalation of chloroethane", the Southern Minnesota Regional Medical Examiner's Office in the United States has confirmed.
The death was ruled an accident by the medical examiner.
The Scottish singer and actor was found dead in his US apartment, in Rochester, Minnesota, last month at the age of 41.
Autopsy documents obtained by the PA news agency listed "toxic effects of chloroethane" as well as "suffocation" as having contributed to his death.
A statement released by Mr Danesh's family previously said local police had found "no signs of intent or suspicious circumstances".
Darius Campbell Danesh was known as Darius Danesh when he made his first bid for fame in ITV show Popstars in 2001 and also appeared on the first Pop Idol, which was won by Will Young.
After Pop Idol, Danesh turned down Simon Cowell's offer of a record deal and signed with producer Steve Lillywhite, whose credits include U2 and the Rolling Stones.
In 2011, speaking about reprising the role of scheming lawyer Flynn in 'Chicago', he said he had based his portrayal of the character on his old mentor and Pop Idol judge, Mr Cowell.
He said: "He's the consummate businessman and a wonderful guy and there's a lot of Simon Cowell in Billy Flynn in terms of the way he approaches things and I recognise that in terms of the character."
He credited Mr Cowell with persuading him to take on the role in Chicago in the first place.
He said: "I'm incredibly grateful for the experiences I've had and all the opportunities that it opened up and to be able to call Simon Cowell a friend and to be able to have dinner with him."
