Fans of George R.R. Martin's "A Song of Ice and Fire" series have started taking clues wherever they can to find out when the next installment, "The Winds of Winter," will be arriving. The author previously said that he hopes to release the book before "Game of Thrones" premieres its sixth season next year, and many thought that the book will most likely be released in April or May 2016.

Now, a new theory that backs a spring release for the novel has come up, and it is tied with Martin's recent cameo on the Syfy channel's "Z Nation."

Martin appeared in the series in its Oct. 30 episode as a zombified version of himself, and the author is seen inside a "celebrity zombie room" and being presented to a collector. The collector seemed to be unfamiliar with the author, and he was told by Martin's captor that the author wrote "A Song of Ice and Fire."

The man said that Martin is the only zombie celebrity that he has so far, and that he was using his muscle memory to autograph novels. Martin was then seen signing copies of a book titled "A Promise of Spring," and his captor bragged that he had hundreds of the new book and that he was going to be rich when Ebay came back.

Fans immediately speculated that Martin must be sending out a message using the title of the book and that he will be keeping his promise to release "The Winds of Winter" very soon, perhaps by spring. When the author promoted his cameo on his blog, commenters applauded him for the teaser as one fan said that his appearance on the show provided more "evidence" for "crazy theories" that he was already done with his sixth book.

"Mr. Martin, you sure know how to tease a hopeful fan base!" said one fan about the title of his prop book. "But you know, we'll take whatever we can get."