The e-book subscription service has teamed with J.K. Rowling's Pottermore to make the Harry Potter e-book available to Oyster subscribers. Now Oyster users can access the seven Harry Potter e-books, as well as the Hogwarts Library, the three additional books Rowling wrote about the Harry Potter world.

The addition of the mega-selling fantasy book series to Oyster is the latest indication of the growing popularity of e-book subscription among publishers as well as consumers. Oyster recently announced that it offers more than 1 millions titles, available to read online and offline, for $9.95 a month.

To mark the addition of the Harry Potter series, Oyster has created a series of backdrop designs based on the “House Themes”—the competing houses that make up the Hogwarts school—of the series. Readers can choose whichever design they prefer as a backdrop for reading. In addition, the Oyster Review, the service's online literary journal/book recommendation site, will feature additional Harry Potter content from January 28-30

Oyster CEO Eric Stromberg said, that since Oyster launched in 2013, "the Harry Potter titles have consistently been some of the most requested books by our readers. About a year ago, we began discussions with J.K. Rowling's Pottermore to bring Harry Potter to Oyster. Today, we're excited to bring the biggest book series of all time to Oyster, while giving readers a new way to enjoy the books."