Muhammad Ali: Celebrities and athletes mourn the boxing legend

An outpouring of tributes flooded social media following the death of three-time heavyweight champion Muhammad Ali, who battled Parkinson's syndrome for 32 years, on Friday night.

Former professional athlete Mike Tyson, Caitlyn Jenner and Floyd Mayweather were among those who mourned the loss of the boxing great. Tyson tweeted that "God came for his champion," while Mayweather wrote, "Not a day went by entering the gym that I didn't think of you. Your charisma, your charm and above all, your class are all of the elements that will be greatly missed by myself and the world."

Read more Hollywood reactions below.

Read More Muhammad Ali, 'The Greatest' Boxing Legend, Dies at 74