Robert Downey Jr. is mourning the death of his "brother" Jimmy Rich.
On Thursday, the "Iron Man" actor announced his assistant and friend died the night before in a car crash.
"This is not news," he wrote on Instagram. "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," Downey reflected. "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."
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"Again, my condolences to his beautiful family, and the legacy of hope and redemption his life will continue to represent."
"Guardians of the Galaxy" star Chris Pratt commented, "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."
Ruffalo said Rich was "such a good man."
"I have known him almost as long as I have known you, Robert," Ruffalo said. "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."
"Captain America" star Chris Evans separately acknowledged Rich's death on his Instagram. The The 39-year-old actor shared a photo of him and Rich on the set of one of the Marvel films, captioning the photo, "I don't have the words. Jimmy Rich was unlike anyone else. He left an indelible impression on everyone he met. No one more so than my brother @robertdowneyjr They were inseparable."
"I'm sending all my love to Jimmy's friends and family," Evans shared. "Be sure to hug your loved ones tightly and please take the time today to show Downey how many people love him and are here for him during this incredibly dark time."
According to Rich's IMDB page, he began working as Downey Jr.'s assistant in 2003. Over the years, Rich shared numerous photos and videos of their time on the set of "Sherlock Holmes," "Dolittle" and "Iron Man."