Recently, a clip from Sesame Street in which some fans could hear Grover using the f-word appeared online. Although his usage of the swear word is an auditory illusion, the bizarre occurrence left some fans wondering just what exactly was going on. Actor and puppeteer Frank Oz, who has played Grover for over four decades, has now responded to that clip, and he's not happy.Oz, responding to a tweet from Star Wars actor Mark Hamill, expressed his disbelief that anyone would think a character on the popular children's show would use a swear word. "Wait," he wrote. "You mean some of you out there seriously believe that Grover on Sesame Street would say the word 'fuck' — on camera or off-camera? Really????"RELATED: Original Big Bird Is Retiring From Sesame Street After 50 Years

Oz also addressed the notion that actors on Sesame Street purposefully make their characters do inappropriate things off camera and dismissed the notion that the show's actors use language while in character. "We don’t," he wrote. "It would be a betrayal of the character’s purity."

In the original clip, viewers report hearing two different lines. In one instance, fans hear Grover saying, "Yes, yes, that sounds like an excellent idea." However, some people hear the popular character saying, "that's a f***ing excellent idea." The former is, of course, what he is actually saying.

Oz is known for his iconic portrayals of such characters as Yoda, Fozzie Bear, Miss Piggy, Cookie Monster and Bert. As a director, Oz has helmed such films as 1986's Little Shop of Horrors, 1988's Dirty Rotten Scoundrels and 2007's Death at a Funeral. Although Oz semi-retired from Sesame Street in 2001, he still occasionally voices the characters he helped pioneer. Actor Eric Jacobson now primarily voices Grover.

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Also a veteran of The Muppets, Oz critiqued Disney's writing of the popular characters earlier this month, saying, "So far the writers Disney has employed don’t know to write for The Muppets. I imagine their hubris makes them believe they can. But the characters need writing that has depth and honesty. I suppose a version of The Muppets will survive. But they won’t be true."