"We are heartbroken to hear this sad news about Grant. He was an important part of our Discovery family and a really wonderful man," Discovery wrote in a statement on its website.
Imahara also hosted the Netflix show White Rabbit Project, which aired in 2016.
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One of the first to pay tribute to Imahara was his Mythbusters co-star Adam Savage, who remembered him as a brilliant engineer and a generous and gentle person.
"Working with Grant was so much fun. I'll miss my friend," he wrote in a tweet on Monday evening.
Before he began hosting shows, Imahara worked in special effects for nine years at George Lucas' Industrial Light and Magic.
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Imahara was a native of Los Angeles and trained as an electrical engineer at the University of Southern California before becoming known as a robotics expert.
According to the Discovery website, he created a custom circuit for the Energizer Bunny and was behind the electronics installation and radio programming on the current generation of bunnies.