CENTER CITY (WPVI) --Many Harry Potter fans are no doubt still celebrating Sunday morning.
The newest book in the Potter series, "Harry Potter and the Cursed Child," hit store shelves at midnight.
Bookstores including the Barnes and Noble in Rittenhouse Square held a release party.
For many fans it was a chance to relive their childhoods.
"I've been coming to this Barnes and Noble for the midnight release since they first started so it was the chance to relive it again and get to come and get the book at midnight," Tarvea Byrd of Philadelphia said.
"I've been following Harry Potter since I was in first grade and now I'm going to be a sophomore in college so it's been a long ride," Abby Lemmon of Media, Pa. said.
The release of "Harry Potter and the Cursed Child" coincides with a play that's premiering in London.
The boy wizard is still as popular as ever.
Both Amazon and Barnes and Noble say this is their most pre-ordered book - since the last Harry Potter release.
The stage play "Harry Potter and the Cursed Child" had its gala opening Saturday in London's West End and is already the theater event of the year.
J.K. Rowling joined director John Tiffany, playwright Jack Thorne and the cast onstage to receive a raucous standing ovation at the end of the two-part show at London's Palace Theatre, where it's scheduled to run at least until December 2017.
If the boy wizard's creator has her way, that will only be the beginning.
"I'd like as many Potter fans to see it as possible," Rowling said on the red carpet before the show, as fans cheered and poked camera phones over crowd barriers in hope of getting a picture.
There's already talk of a Broadway run, and Rowling said: "I'd like it to go wider than that."
Sunday marks Rowling's 51st birthday. It is also Harry Potter's birthday, according to the books.
The Associated Press contributed to this report.