It's September 23. That can only mean one thing. It's Batman Day. To Celebrate, composer Danny Elfman took a break from working on his Justice League score, sharing a new video where he wishes fans around the world a very Happy Batman Day. Though some might call it Harley Quinn Day. The official DC Youtube shared the video saying this.

"Happy Batman Day, DC fans! We hope all of you have a great time celebrating the Dark Knight...and so does Batman and Justice League composer Danny Elfman."

Danny Elfman did the score for Tim Burton's 1989 Batman movie. Now, he returns more than twenty years later, providing an all new soundtrack for the next DCEU adventure. Justice League will be in theaters this November. And the new music Danny Elfman is working on will surely please longtime fans.

Warner Bros. recently held a test screening for Justice League. While some have called the work-in-progress epic, those first audiences have seen the movie with a temp soundtrack, as Danny Elfman is still hard at work. Who knows how much better it will be once this music is laid down. Sadly, we don't get to hear any of Danny's new tracks in this 14 second video.

Warner Bros. and DC Comics celebrate Batman day every year. But because this is also Harley Quinn's 25th Anniversary, they are letting her take over. DC explains.

"Join us in celebrating the legendary superhero we all love! Batman Day is Saturday, September 23rd, 2017. Except this year, in celebration of Harley Quinn's 25th anniversary, the Clown Princess of Crime is taking over!"

The annual fan-favorite event, now in its fourth year, was first introduced to honor Batman's 75th anniversary. This year, in honor of Harley Quinn's 25th anniversary, Batman Day will also feature the immensely popular Clown Princess of Crime who burst into our lives when she debuted on Batman: The Animated Series in 1992. Harley Quinn now stars in her own best-selling comic book series, acclaimed graphic novels and has inspired amazing toys and collectibles based on her iconic looks from over two decades. She was the breakout character in the Suicide Squad movie and the Batman: Arkham series of video games, and she was even the most popular Halloween costume of 2016!

There's plenty of exciting things going on in honor of Batman day today. If you want to participate do a web search for your area. You can also celebrate at home by watching the many available Batman movies and TV shows that have been released over the years. Or you can just smile and watch Danny Elfman wish you a happy Batman day from his studio. From ours to yours, we'd all love to wish you a very happy Batman day. Don't let the Joker get you down. Go watch and remember Adam West in the 1960s Batman movie today, and turn that frown upside down.