“I’m in shock. I knew him forever,” Einstein’s Curb costar Richard Lewis tweeted Wedneday. “His role on #curbyourenthusiasm was excruciatingly brilliant! Our cast and crew will be devastated. He was so loved. He told me how much he loved LD and Curb. RIP buddy.”
His brother Albert Brooks, a writer/director best known for Broadcast News, tweeted, “R.I.P. My dear brother Bob Einstein. A great brother, father and husband. A brilliantly funny man. You will be missed forever.”
Prior to his time on the HBO comedy, Einstein made a name for himself as a writer. In the 1960s, he won an Emmy for writing alongside Steve Martin on The Smothers Brothers Comedy Hour. He also earned Emmy nods for his work on The Sonny and Cher Comedy Hour and Dick Van Dyke’s Van Dyke and Company.
As a producer on Van Dyke and Company, he took home an Emmy in 1977 when the show won outstanding comedy series.
Einstein was also the creator of the hilarious Super Dave Osborne character. He appeared as the character on numerous shows throughout his career, including Bizarre and the self-titled Super Dave in the 80s. He last took on the role in 2009 on Super Dave’s SpikeTacular, which he also produced.
This article originally appeared on PEOPLE