Robert Downey Jr has paid tribute to his longtime assistant Jimmy Rich after announcing that he had died in a fatal car accident, aged 52.

The 56-year-old actor shared the tragic news in an Instagram post on Thursday, in which he shared a gallery of photos of his close friend.

Writing on the social media site, Robert shared: "This is not news. This is a terrible and shocking tragedy.

The actor went on to say that Rich had been responsible for keeping him free of drugs since he became his assistant in 2003.

Robert Downey Jr mourns longtime assistant Jimmy Rich
Robert Downey Jr mourns longtime assistant Jimmy Rich

He continued: "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."

Robert has credited Rich and his wife Susan Levin for helping him quit his drug and alcohol habits after a period of time, between 1996 and 2001, in which the actor was arrested multiple times and charged with offences relating to cocaine, heroine, and marijuana.

Robert Downey Jr has shared the tragic news on Instagram
Robert Downey Jr has shared the tragic news on Instagram
Robert Downey Jr has said that Jimmy Rich helped him to get clean and stay clean
Robert Downey Jr has said that Jimmy Rich helped him to get clean and stay clean

Robert concluded his emotional post: "Again, my condolences to his beautiful family, and the legacy of hope and redemption his life will continue to represent.

"Peace Be Unto You."

Robert was joined by fellow Marvel actor Chris Evans in paying tribute to Rich, with the Captain America star sharing a snap of them together.

Writing on Instagram, Chris shared: "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. 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."

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