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".

In a blog post titled 'From Knoxville with Love', Johnny wrote: "You'll have to excuse me, I'm just very sad because I lost my brother and my world got about 134 per cent less funny. I don't know what else to say right now, so I will close with I love you, Ryan. I have a lot of emotions swirling, but I want you to know I love you so very much."

While Johnny says Ryan never failed to make him laugh, he was a great listener and give serious advice.

He wrote: "He had such a hair trigger laugh reflex. He lived his life wanting to laugh and wanting you to laugh with him. He would cackle really loud, too, and it wasn't uncommon that he would fall over from it. "Sometimes I would fall with him because his spirit was very contagious. He was always there if you were sad about something. That's why all this is even harder because right now I really need to talk to him but I can't."

Ryan's close friend Zachary Hartwell was also killed in the crash and a memorial service for Ryan was held last week, which Johnny attended.