As news of Ryan Dunn's passing quickly spread, Johnny Knoxville turned to Twitter to express his grief.
"Today I lost my brother Ryan Dunn," he wrote upon hearing that Dunn had died today in a fiery car crash in Pennsylvania. "My heart goes out to his family and his beloved Angie. RIP Ryan, I love you buddy."
But Knoxville wasn't the only Jackass costar to use the social media site as an outlet to mourn.
As for Steve-O, he shared a similar sentiment. "I don't know what to say, except I love Ryan Dunn and I'm really going to miss him," he wrote.
While there's been no word yet from costar Bam Margera, his mother described Dunn as being "like a son" to her when discussing the accident with a local Philadelphia station this morning.
Earlier today, MTV released the following statement: "We're deeply saddened by the passing of a member of the MTV family, Ryan Dunn. Our hearts and thoughts are with his friends and family."