Robert Downey Jr.'s assistant has died aged 52

He wrote: "This is not news.

This is a terrible and shocking tragedy.

Jimmy Rich was in a fatal car accident at approx. 8pm yesterday. He was a brother, my right hand man, an uncle to our kids and beloved by all who experienced his singular character and wit.. our thoughts go to his relatives, friends, co-workers, and all the fans who knew him as the man who supported every step of my recovery, life and career..

Again, my condolences to his beautiful family, and the legacy of hope and redemption his life will continue to represent.

Peace Be Unto You. (sic)"

Several of the Marvel actor's famous friends paid tribute to Jimmy, including Chris Hemsworth, who praised him as a "wonderful human".

He wrote: "So sorry mate . Absolutely Heartbreaking .Such a wonderful human. He’ll be missed. (sic)"

Jack Black posted: "Heartbroken. Such a good man."

Ryan Reynolds wrote: "So sorry to hear this. Condolences to you and Jimmy’s family. Heartbreaking"

Mark Ruffalo admitted he will miss Jimmy and thanked him for "always being real".

He commented: "Such a tragedy. Such a good man. I have known him almost as long as I have known you, Robert. Breaks my heart to have Jimmy go over to the other world. You will be missed Jimmy. Thanks for always being real, always being there to lend a hand and showing the way of light forward to so many people. Another sad day."

Chris Pratt praised Jimmy as "awesome".

Commenting on Robert's post, he wrote: "Oh no! I’m so sorry man. Im praying his family, you and yours. That sucks so bad. I’m so sorry to hear that. He was awesome. Such a tragedy. (sic)"

Josh Brolin posted: "No words. Just tears and gratitude for the gift that was him."

Jeremy Renner shared: "Wow. Brother. What a devastating loss"