Hamasaki Ayumi has released a new single titled "23rd Monster" on her 23rd debut anniversary day, April 8.

Although this single was supposed to be a complete surprise, there were reports of it being released in other parts of the world at midnight, which created a buzz online. As such, Hamasaki revealed information on the single a few hours before its release, saying, "It's regrettable that it's not a surprise."

"23rd Monster" is a rock number that was composed by Hara Kazuhiro. Hamasaki sings about how one's path must be chosen on their own.

Simultaneously, a video called 'MV teaser -episode 0-' has been uploaded onto YouTube. It features a mysterious countdown timer with dancers giving an aggressive performance around it.