James passed away at the age of 73 in a California hospital today (January 20) following a lengthy battle with leukaemia.
Following a flood of tributes from other celebrities around the world, Beyoncé - who portrayed the 'At Last' performer in 2008 film Cadillac Records - posted her own message on her website praising the "fearless" musical idol.
"This is a huge loss. Etta James was one of the greatest vocalists of our time," she wrote. "I am so fortunate to have met such a queen. Her musical contributions will last a lifetime.
"Playing Etta James taught me so much about myself, and singing her music inspired me to be a stronger artist. When she effortlessly opened her mouth, you could hear her pain and triumph.
"Her deeply emotional way of delivering a song told her story with no filter. She was fearless, and had guts. She will be missed."
Beyoncé named James as one of her "musical heroes" back in 2009.
Recalling being coached by the 'Tell Mama' singer for Cadillac Records, she said at the time: "You can imagine how scary it is when you're singing someone's song dressed as them and they are watching.
"I knew she was very tough and I was really nervous. My heart was racing. At the end, I hugged her and wanted to cry."
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Watch Beyoncé sing 'I'd Rather Go Blind' by Etta James for Cadillac Records below: