Happy birthday, J.K. Rowling!

The author of the Harry Potter series turned 54 years old on Wednesday. To celebrate, Emma Watson shared an old photo of the duo hanging out at a costume party with her co-star Evanna Lynch. The Hermoine Granger star dressed as Wonder Woman in the photo while the Luna Lovegood character donned a cute cat number. Rowling also shielded part of her face with a mask.

"Sexy and scary!" the actress wrote on Instagram. "You smashed this. All the love to you Jo. Happy Birthday!!!! Extra points to @msevylynch for being the most perfect cat."

Of course, a few Potterheads couldn't resist commenting on the caption.

"30 points to Gryffindor," one follower wrote.

As excited as fans were, nobody seemed more thrilled about the throwback than Lynch.

"Ahhhh I didn't know this photo existed," she wrote in the comments section.

Rowling isn't the only one in the Wizarding World celebrating a big day today. As fans are well aware, it's Harry Potter's birthday, too. The character, played by Daniel Radcliffe in the movies, is now 39.

ncG1vNJzZmivp6x7prvNpaCnnV6YvK57zZ6urGdhZYNyfJZxZp6lnZZ6uK3TrKanZZees7W%2FjKGYq6qpYr2wwNOeqWaekaPAbq2MrJyxsV2Wu6V50pyYq7FdpbWwwM5mpqdlmmK4br7OsKOippdiwG6uyKuroZyRrg%3D%3D