Will Young has paid tribute to “driven, courageous and gentle” Darius Campbell Danesh on what would have been the Pop Idol star’s 42nd birthday.

The family of the Scottish singer-songwriter and actor announced he had died in his US apartment on Tuesday.

Young, 43, who starred alongside Campbell Danesh on Pop Idol, remembered his friend in a heartfelt tribute on Instagram, writing: “For the past few days my thoughts have been with Darius’s family and will continue to be so.

“I found this picture a while ago taken during Pop Idol. If there was ever an example of not giving up on your dreams then Darius is top of the pile.

“Driven, courageous and gentle. My love goes to his family at this time x”

Brit Award-winner Young won the inaugural series of Pop Idol in 2002 on which Campbell Danesh also competed.

In the early hours of Friday morning Gerard Butler also paid tribute to his late friend, describing him as his “brother in arms”.

Butler, who was pictured with Campbell Danesh in Malibu shortly before his death, shared a photo online of the pair together smiling, along with the caption: “I am devastated by the sudden passing of my dear friend Darius, a true brother in arms. My thoughts and love go to his wonderful mum and dad Avril and Booth and his two brilliant brothers Aria and Cyrus.

“To those lucky enough to have met Darius for more than a few minutes, they were deeply moved by his infectious laugh and barely containable zest for life.

“He was always armed with a smile, a booming voice, and a genuinely warm embrace that few could resist-nor would they want to!!! He was an incredible talent, a singer whose voice touched your soul and an actor with great presence.

“But, most importantly, he had the heart of a lion. It was bigger and brighter than the sun and an energy so contagious he could light up a room in seconds.”

The singer was known as Darius Danesh when he made his first bid for fame on ITV show Popstars in 2001.

He then went on to star on Pop Idol, and after coming third on the show turned down Simon Cowell’s offer of a record deal and signed with music titan Steve Lillywhite.

“Our boy Darius was always constant and unwavering in his passion for life,” Butler continued.

“But a bigger constant was his dream to inspire others to better themselves. He talked the talk but boy, did he walk the walk. He had such purity of thought, a deep wisdom and constant gratitude for people, for life, a compassion towards all.”

Butler finished his post saying: “But something tells me there will be way more waves created by our boy Darius further down the line. My heart aches heavily. But going forward, I will beat my drum louder and celebrate life and its every beautiful moment because my brother showed me that was a pretty awesome way to go about it.”

Butler, 51, who is best known for films such as 300, Law Abiding Citizen and Olympus Has Fallen and its sequels, said his friend was driven to “inspire others to better themselves”.

Campbell Danesh’s debut single, Colourblind, was released in July 2002 and went straight to number one, marking the start of a run of top 10 releases.

Since his death the song has re-entered music charts and on Wednesday morning was in top spot on the iTunes download chart.

Campbell Danesh’s family said in a statement he 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”.

Local police confirmed there were “no signs of intent or suspicious circumstances”, with the cause of his death unknown at this stage, the family added.

Former Pop Idol judges Simon Cowell, Pete Waterman and the runner-up from the first series, Gareth Gates, also paid tribute to Campbell Danesh following the news.