Former Goldman Sachs executive Greg Smith, who grabbed headlines for his op-ed takedown of the storied investment bank, is set to release a tell-all in October.

The 288-page book, titled “Why I left Goldman Sachs: A Wall Street Story,” comes seven months after the former executive director wrote a poison-pen opinion piece in the New York Times, claiming the bank had lost its way.

One of Smith’s allegations was that Goldman workers in its London office referred to clients as “muppets”— British slang for idiots.

Goldman responded by portraying Smith as a mid-level employee who overstated his role at the firm.

“Not a single person reported to him, and he did not run a business,” Goldman spokesman David Wells said. “We hope the rest of his book is more accurate.”

The book, set for Oct. 22, is being published by Grand Central Publishing, a division of France-based Hatchette Book Group. Smith reportedly scored a $1.5 million advance — roughly three times what he earned at the bank, according to one Goldman insider.