O'Neal passed away after suffering a stroke last month (Oct11) and the Platoon star has paid a touching tribute to the funnyman, who he met for the first time in September (11), days before he poked fun at the actor at the Comedy Central Roast of Charlie Sheen.
In a statement, Sheen says, "The entertainment world as well as the world at large lost a brilliant man today. Patrice had that rare 'light' around him and inside of him. I only knew him for the few days leading up the Roast. Yet I will forever be inspired by his nobility, his grace and his epic talent.
"My tears today are for the tremendous loss to his true friends and loving family."
Actress Kate Walsh, who also took part in the Sheen roast, and a host of other stars have also expressed their sadness.
Taking to her Twitter.com page, Walsh writes, "God Bless Patrice O' Neal, I'm so glad I got to meet you and hear your funny f'in words. A truly singular voice. RIP".
And actor/comedian Denis Leary tweets, "Patrice O'Neal. One of the funniest men who ever walked this earth. RIP."
Meanwhile, Ricky Gervais has called the late comic "one of my favourite stand-up comedians," and Nick Cannon insists O'Neal was "an amazing comedian and an even better person."