Dunn, 34, and an unidentified person both died early Monday when their Porsche crashed in West Goshen Township — which happens to be the home of QVC — outside Philadelphia, according to local police. The car flew over the guardrail, slammed into a tree and burst into flames.
About two hours before the accident, a photo was posted on Dunn's Tumblr of him drinking with friends.
"We're deeply saddened by the passing of a member of the MTV family, Ryan Dunn," MTV said on Twitter early Monday morning. "Our hearts and thoughts are with his friends and family."
Jackass star Johnny Knoxville also reacted to the news on Twitter, linking to a photo of Dunn on a bike in an Evel Knievel-esque jumpsuit. "Today I lost my brother Ryan Dunn. My heart goes out to his family and his beloved Angie," he wrote. "RIP Ryan, I love you buddy."
Dunn is most famous for his MTV series and the spin-off movies in which he had a penchant for crashing golf carts and sticking toys up his rectum.
See Dunn's final television appearance on Minute to Win It: