A twitter post by George RR Martin with the words "It's Publication Day" has thrown off some fans who thought that the tweet is in reference to Martin's "The Winds of Winter." However, the tweet is actually to promote "Ace in the Hole."

The George RR Martin "It's Publication Day" tweet surprised a number of "A Song of Ice and Fire" fans especially those who were only able to read the caption. Fans of the book series, which is where the hit HBO TV series "Game of Thrones" is based, thought that the tweet was in reference to the highly anticipated George RR Martin "The Winds of Winter" novel.

"The Winds of Winter" is the sixth installation of the "A Song of Ice and Fire" series written by George RR Martin. There have been a number of speculations as to when "The Winds of Winter" release date will be, however, no concrete details have been announced.

Fans of the "A Song of Ice and Fire" book series and the hit TV series "Game of Thrones" were thrilled when George RR Matin wrote in his livejournal that "The Winds of Winter" may be published this year. However, the author also said that he also thought the same thing in 2016.

Though there have been speculations that "The Winds of Winter" will be released this year, they remain to be nothing but speculations. A report also suggested that the sixth novel in the "A Song of Ice and Fire" series will be published within 2015-2018, taking into consideration George RR Martin's writing pace in the past installations of the series.

Fans may just have to wait until an official "The Winds of Winter" release date announcement is made. Fans can also constantly monitor the author's live journal. George RR Martin said that he will inform "A Song of Ice and Fire" fans a month before the official release of the sixth novel.