"Float like a butterfly, sting like a bee" — chances are, you've heard the poetic phrase before, but did you know it was coined by the late, great boxing legend, Muhammad Ali?

Certainly, the World Heavyweight Champion will be remembered for his athletic triumphs in the ring, but the man was also a prolific wordsmith, global humanitarian, and human rights advocate, his influence reaching much farther than simply the tournaments in which he entertained sports lovers worldwide. As news of his June 3 passing became known early Saturday morning (June 4), celebrities, political icons, sports stars, media giants and more have begun to share their condolences, personal stories, and emotional tributes across social media.

While music artists like Jennifer Lopez and Justin Timberlake expressed the loss of their hero in words, other industry icons like Oprah, Lionel Richie and Elton John have posted nostalgic throwback photos of themselves with "The Greatest of All Time," making it clear that Ali's legacy remains very much alive within the hearts of those he touched.

From quotes to photos to video clips, see how Ali's famous friends, competitors, and the celebrities he inspired are celebrating his prolific, poignant life — as well as mourning the loss of a true, irreplaceable American icon.

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