Johnny Knoxville says his world is now "134 per cent" less funny following the death of his 'Jackass' co-star Ryan Dunn.

The 34-year-old daredevil died when his Porsche veered off the road, crashed into a tree and burst into flames last week and Johnny says he's been left devastated by the tragedy because he's lost a "brother".

Ryan Dunn was reportedly twice over the legal alcohol limit when he crashed his car.

The 'Jackass' star - who died when his Porsche veered off road, crashed into a tree and burst into flames on Monday (20.06.11) - had a blood alcohol level of .196, nearly two-and-a-half times the legal limit in Pennsylvania which is set at .08.

'Jackass' star Ryan Dunn's death was so violent it is unknown if it was caused by the car crash or the subsequent fire.

The autopsy result for the actor and Zachary Hartwell - who was also killed when Ryan's Porsche flew over a barrier and into a tree on Route 332 yesterday (20.06.11) - were both dead when officers arrived on the scene, and according to TMZ.com the Chester County Coroner has confirmed it is impossible to determine how they died.

Johnny Knoxville has paid tribute to his 'Jackass' co-star Ryan Dunn, who died in a car crash earlier this morning (20.06.11).

The 40-year-old star hailed Ryan - whose car flew over a guardrail on Route 322, hitting a tree before bursting into flames at around 3am - as his "brother" on social networking site twitter, adding he "loved" him.

'Jackass' star Ryan Dunn has died.

The 34-year-old daredevil and an unnamed second person passed away in a car crash in Pennsylvania early this morning (20.06.11), April Margera - the mother of his 'Jackass' co-star and close friend Bam Margera - has confirmed to gossip website TMZ.