Celebrities have come together to pay tribute to Ryan Dunn, who died in a horrific high-speed car crash in the early hours of Monday morning.

The ‘Jackass’ star, aged 34, and his pal Zachary Hartwell, were killed after the stuntman’s Porsche reportedly careered off the road and burst into flames in Pennsylvania.

Leading floods of heart-felt messages on Twitter was his close buddy and MTV co-star Steve-O, who told fans,

“I don’t know what to say, except I love Ryan Dunn and I’m really going to miss him.”

Good Charlotte guitarist Benji Madden also paid his respects to the star online, posting,

“I’m very Sad and Shocked to hear about Ryan Dunn,” while his bandmate and brother Joel added, “R.I.P Ryan Dunn. Very sad news.”

‘Hills’ star Brody Jenner expressed his condolences too, writing,

“Just heard about Ryan Dunn… So sad.. #RIPRYANDUNN.”

And popstar Jessica Simpson, who starred in the flick ‘Blonde Ambition’ alongside the famous daredevil, added,

“It has taken me all day to put my thoughts into words, but there are no words to describe the loss of such an incredible man. RIP Ryan Dunn.”

Relive some of Ryan's best moments in ‘Bam’s Unholy Union’ this Saturday (June 25) @ 9am - followed by ‘Jackass’ @ 1.30pm on MTV Australia.

Meanwhile, remember Ryan with photos from his life below…

Ryan Dunn | A Career In Photos

Ryan Dunn | A Career In Photos

Sean Gresens/MTV

Ryan Dunn.

  • Sean Gresens/MTV

    Ryan Dunn.

  • Ron Galella/WireImage

    Ryan Dunn, Johnny Knoxville and Travis Barker on August 29, 2002.

  • Angie Cuturic and Dunn at the premiere of 'Jackass: The Movie' October 21, 2002.

  • Dunn at the UK premiere of 'Jackass: The Movie' on February 25, 2003.

  • Dunn on February 19, 2004.

  • Bam Margera and Dunn appear on 'TRL' on April 23, 2004.

  • Getty Images

    Dunn appears on 'TRL' on October 31, 2005.

  • Getty Images

    Dunn at the 2006 VMAs press forum on August 30, 2006.

  • Dunn and Bam Margera on August 10, 2008.

  • The cast of 'Jackass' at the 2010 VMAs on September 12, 2010.

  • Getty Images

    Dunn on March 7, 2011.

Copyright : MTV Australia