amazonharrypotter11It’s Harry Potter.

Amazon’s “secret product” release at midnight on Sunday, which we first reported on last week, is the new Harry Potter book, Harry Potter and the Cursed Child.

On the Prime Now mobile app, Amazon is notifying customers of “midnight delivery” for the book.

“On 7/30, order from 9:45 p.m. to 11:30 p.m. for delivery between midnight and 2am on 7/31,” Amazon notes.

Amazon sent emails to Amazon Flex delivery drivers earlier this month, asking for people available July 31 from midnight until 2 a.m.

“At 12:01 a.m. on Sunday, July 31st, Amazon customers will be able to get their hands on a brand new product,” the email read. “We are not able to share with you what this product is until the launch time, but you could be one of the first in the world to see it by delivering during a block created just for this release!”

It’s certainly a peculiar time frame for a product launch — Amazon Flex drivers typically work until 12:30 a.m. at the latest — but makes sense given that it’s a Harry Potter book. July 31st also happens to be the birthday of author J.K. Rowling, as well as Harry Potter. This is the eighth official installment of the Harry Potter series and is actually a playscript for the first Harry Potter story to be produced on stage.

Other brick-and-mortar bookstores in Seattle are doing midnight release events of their own. The Elliott Bay Book Company and the downtown Barnes & Noble stores, for example, will be open at midnight on Sunday for the release.

Meanwhile, Amazon’s bookstore in Seattle — the company’s first-ever physical retail shop — is not doing a midnight release. However, a store employee said that Amazon is tracking how many people inquire about a midnight release.

There is certainly demand for the book, which is already topping best-seller lists for 2016.

Amazon did a similar midnight delivery promotion this past November, when it offered the new Call of Duty game to Prime members. Sunday’s product launch on July 31 appears to be only for Prime members, too.

Those who want the Kindle version of the Harry Potter book can place a pre-order and receive it at midnight local time on July 31, TIME reported.

The Amazon Flex program, first reported by GeekWire in August, is an Uber-style delivery network that enables private drivers who use their own vehicles to deliver packages. It started in Seattle this past fall and is now live in nearly 30 cities.

Like what you're reading? Subscribe to GeekWire's free newsletters to catch every headline

Job Listings on GeekWork

Find more jobs on GeekWork. Employers, post a job here.