In a statement released on Tuesday afternoon, the family of the singer and West End star revealed that he had been found unresponsive at his home in Minnesota on Thursday, and was pronounced dead later that day.
In a statement given to the PA news agency, former Pop Idol judge Simon remembered Darius as “charismatic” and “funny” and said his death was “absolute tragedy”.
“I first saw Darius on television over 20 years ago and I got to know him really well,” Simon. said.
“He was charismatic, funny and just a great person to be with.
“His passing, for someone so young, is an absolute tragedy and my heart goes out to his family and friends.”
Announcing his death on Tuesday, Darius’ family said: “It is with great sadness that we announce the passing of Darius Campbell Danesh.
“Darius was found unresponsive in bed in his apartment room in Rochester, Minnesota, on August 11 and was pronounced dead in the afternoon by the local medical examiners’ office.
“The local police department have confirmed that there were no signs of intent or suspicious circumstances. The cause of his sudden death is unknown at this stage while medical examinations continue.
“We ask that you kindly respect our wishes for privacy at this time whilst we come to terms with the tragic loss of our son and brother.”
The cause of death remains unknown.
The Scottish singer-songwriter and actor – who was known as Darius Danesh when he made his first bid for fame in ITV’s Popstars in 2001 – also appeared on the first Pop Idol, which was won by Will Young.
Gareth Gates, who found fame after finishing as a runner-up on the first series of Pop Idol, also paid tribute in a touching Instagram post.
Alongside a picture of himself and Darius, the 38-year-old wrote: “I can’t quite believe the news of my dear friend Darius passing. I’m heartbroken.
“Darius took me under his wing during our time in Pop Idol, like a big brother; always looking out for me and for that I thank you my friend.
“I will miss our chats. He was one of the most beautiful, intelligent and gentle souls I was lucky enough to know, a soul that lit up every room.
“Good bye my friend. Forever in my heart x.”
Myleene Klass, the former member of pop group Hear’Say, which was formed on Popstars, shared a clip of Darius performing, which she captioned “Everyone should watch this performance. Darius, you were so talented, so kind. A true family man. My thoughts are with them now.x”
Liberty X member Michelle Heaton, who also competed on Popstars, remembered Campbell Danesh’s rendition of …Baby One More Time from his Popstars audition.
She tweeted: “So sad… thoughts with Darius family right now x always our Britney.”
After Pop Idol, Darius turned down Simon Cowell’s offer of a record deal and signed with producer Steve Lillywhite, whose credits include U2 and the Rolling Stones.
His debut single, Colourblind, was released in July 2002 and went straight to number one, marking the start of a run of top 10 releases.
He went on to forge a successful stage career, appearing in Chicago as Billy Flynn in two runs of the production, as well as Guys And Dolls, Gone With The Wind and other West End shows.
Darius credited Simon 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.”
Darius lived in the US and found love with Canadian actress Natasha Henstridge, whose films include sci-fi hit Species.
The couple married in 2011 at the San Ysidro Ranch in Santa Barbara, California, but were divorced a few years later.