Roger Ebert aside, Twitter celebs mourn Ryan Dunn

A wealth of celebrities have voiced their sadness over the death of Ryan Dunn Monday morning.

Jackass co-star and longtime friend Steve-O wrote I don't know what to say, except I love Ryan Dunn and I'm really going to miss him. Steve-O cancelled a number of a-up comedy gigs in San Francisco because of Dunn's death.

She's All That actress Rachael Leigh Cook tweeted Monday that she was deeply saddened to hear of Ryan Dunn's passing. She later added that Dunn was an incredibly funny, kind, and generous person. My heart goes out to Angie & his family.

Carey Hart, a freestyle motocross champion, simply said RIP Ryan Dunn. You were an amazing guy and you were cut way to short. Enjoyed the times we had. My heart goes out to his family and friends.

Film director Sofia Coppola, who has made such films as Lost in Translation and The Virgin Suicides, wrote Ryan Dunn has passed away, he was a very nice and energetic guy, I met him a couple of times. Very shocked.

Meanwhile, a Twitter feud has erupted between Pulitzer Prize winning film critic Roger Ebert and Dunn's best friend and Jackass co-star Bam Margera.

On Monday, Ebert tweeted: Friends don't let jackasses drink and drive.

This enraged Margera, who fired back: I just lost my best friend, I have been crying hysterical for a full day and piece of s**t roger Ebert has the gall to put in his 2 cents about a jackass drunk driving and [he is] one, f*** you!