'80s pop icon George Michael passed away on Christmas (Dec. 25), causing many stars to pause their holiday celebrations to remember the singer. Among the artists to pay tribute to Michael was Carrie Underwood, a big fan of his.

In an Instagram post, Underwood remembered Michael, whom she cites as one of her major influences.

"I never told him (mainly because I thought I'd freak him out), but #georgemichael has always been such an influence on me," Underwood writes. "As a child, his was the first voice I could pick out of the sea of voices I heard on the radio. Before I knew anything about him, I knew his voice. As an adult, I cried when I saw him in concert. His songs and his voice helped to teach me how to sing."

Now that Michael is gone, however, Underwood says that she "will forever regret not letting him know" how much he meant to her.

"Thank you, George, for giving the world your gifts," Underwood concludes. "May you rest in peace."

Michael first rose to fame as part of the '80s duo Wham!; the group's hits included "Wake Me Up Before You Go-Go," "Careless Whisper" and "Last Christmas." Michael also had a successful solo career, however: His debut solo studio album, 1987's Faith, earned Album of the Year at the Grammy Awards, and has sold more than 25 million copies.

According to the BBC, Michael died “peacefully,” at the age of 53, at his home in Goring-on-Thames, which is located in Oxfordshire, England; Michael's manager tells the Hollywood Reporter that he died of heart failure.

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