Michael Johns Dies Aug. 1: Celebs Mourn Aussie Singer's Death; Simon Cowell, AI Celebs, Josh Groban Pay Tribute on Twitter [Watch Johns' Idol Audition Video]

Michael Johns, an American Idol alum, died Aug. 1. He was 35. Various reports link the death to an ankle injury, which reportedly caused a blood clot. The Australian singer suffered "swelling and bruising" from his ankle "up to his leg." Former AI judge Simon Cowell, other Idol celebs and Josh Groban join many others on Twitter in paying tribute to the AI Season 7 finalist.

"Sources close to Michael Johns tell us he went to a doctor on Thursday to check out the pain he had been feeling in his ankle ... the swelling and bruising had made their way up to his leg," TMZ reported. The report mentioned the doctor "didn't find any problems."

"I just heard the very sad news that Michael Johns has passed away. A truly great guy. Rest in peace Michael," Simon Cowell said on Twitter.

Born on Oct. 20, 1978 in Perth, Michael Johns was turning 29 when he auditioned on American Idol Season 7. His early exit was met by loud boos from the live audience, many of whom predicted he would stay longer in the competition. Still, Johns' music career progressed well. He released an album called "Hold Back My Heart" (2009) and has worked with David Foster (as noted by Josh Groban in his Twitter tribute).

According to The Hollywood Reporter, Michael Johns was "a favorite of Grammy-winning producer David Foster." The Idol alum also "participated in many A-list charity events."

Ryan Seacrest, American Idol host for 13 seasons and counting, said on Twitter Michael Johns was a "consistently kind guy with talent for days."

"He was a part of our American Idol family and he will be truly missed," FOX said in a statement.

David Archuleta and David Cook were the Final Two in American Idol Season 7. Cook took home the title. Archuleta calls Michael Johns his "Australian buddy." Cook's last Twitter update was posted Jul. 28.

Josh Groban says Michael Johns was 'a wonderful guy'

Oh no. @michael_johns has passed away. Such a wonderful guy and a great voice. Hung with him many times with @officialdfoster. Awful. RIP.
— josh groban (@joshgroban) August 2, 2014

American Idol Season 7 Runner-up David Archuleta calls Michael John his 'Australian buddy'

Remembering a friend this weekend, Michael Johns, and keeping his family in my prayers. You'll be missed, Australian buddy. #RIPMichaelJohns — David Archuleta (@DavidArchie) August 3, 2014