"Crazy 4 U" is Kumi Koda's tenth single and last single released before her studio album feel my mind. It failed to chart in the top ten on Oricon, coming it at #12. Despite its low ranking, it remained on the charts for six weeks.

The single contained one B-side, "Yume with You" (夢 with You / Dream with You), which was a cover of the same song originally performed by Toshinobu Kubota in 1993. It also contained a remix of the title track. This was also the single that kick-started the ero-kawaii craze that Kumi became synonymous with, and that spread across teens and young adults in Japan. Crazy 4 U became a milestone in Kumi's growth as an artist, with her enjoying the theme and beginning to choose the songs she would perform.

"Crazy 4 U" was the opening theme of the Japanese anime series Gilgamesh.

The corresponding music video was released on Koda Kumi's DVD feel..., and later on her first compilation album, Best ~first things~. In 2006, a dance version was released on her compilation album Best ~Bounce & Lovers~.

The music video for "Crazy 4 U" was not coupled with the single, but was placed on the corresponding DVD to feel my mind, feel....

The music video had an espionage theme, with Kumi acting as an agent to track down a smuggler. Throughout the video, she attempts to locate the smuggler, meeting an innocent party girl in the process, who winds up involved unknowingly.

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Wikipedia