J.K. Rowling just revealed another awesome detail about Harry Potter's son James

Today has been a banner day for J.K. Rowling's Twitter followers — the "Harry Potter" author just revealed another major detail about the characters' lives after book seven. 

Earlier Tuesday, Rowling tweeted that Sept. 1 marked the first day of Hogwarts for James Potter, son of Harry Potter and Ginny Weasley. Now, she's announced via Twitter that James has officially been sorted into Gryffindor.

Here's that tweet. It's already been retweeted over 42,000 times. 

—J.K. Rowling (@jk_rowling) September 1, 2015

Rowling also dropped another plot detail in her tweet. Teddy Lupin, son of aurors Remus Lupin and Nymphadora Tonks, is a Hufflepuff. And he's head boy too. 

Despite the happy occasion, many Twitter users were saddened to see that James hadn't been sorted into Slytherin. 

—Ella Dawson (@brosandprose) September 1, 2015

—nana (@buddhaforjared) September 1, 2015

 Maybe they'll have better luck when Harry Potter's other son, Albus Severus Potter, heads for Hogwarts in 2017.