"Fifty Shades of Grey" author E.L. James hinted that she could be working on the fourth book of the series, according to her latest post in Instagram.

The author posted an intriguing photo in her Instagram account and teased her fans and followers that the fourth installment on the love story of Christian Grey and Anastacia Steele may be on its way.

James posted a photo of her keyboard without a caption or explanation last Sunday that prompted her fans and followers to assume that she was writing a new novel to add in her serial trilogy because the photo was zoomed in on the letters that make up the word "F-I-F-T-Y".

The author neither confirmed nor denied the rumors but James' followers quickly swarmed the post with likes and comments asking the author to confirm whether she will be writing fourth book of the best-selling "Fifty Shades of Grey" trilogy. Many fans hoped that another book could be on the horizon.

This is not the first time that James hinted on the possibility of adding another book to the franchise. When a fan asked whether she was planning to write a fourth book, James responded "Never say never". Moreover, in her interview with Hollywood Reporter in November 2012, she was asked what are the odds of her writing another book;

"I have to think about it," James answered, adding, "I have to really think about Christian's point of view. So it's about what to do next."

"Fifty Shades of Grey" is an adult novel that started as fan fiction based on the "Twilight" series. The story revolved around the BDSM relationship of billionaire Christian Grey and virgin Anastacia Steele. The movie adaptation of the first book of the trilogy will hit the theaters on February 13, 2015 with Dakota Johnson and Jamie Dornan starring as Anastacia Steele and Christian Grey.