Do As Infinity was a popular Japanese band which debuted on September 29 1999 with the release of their first single, "Tangerine Dream". Their name is sometimes abbreviated as D.A.I., revealing that Do As Infinity was named after the band's guitarist and composer, Dai Nagao. With the release of their A-side compilation album Do the A side, Do As Infinity disbanded on September 29 2005, after a career which spanned six years, six albums, twenty singles, seven compilation albums and eight live DVDs.

Consisting of Tomiko Van (vocalist), Ryo Owatari (guitarist), and Dai Nagao (composer), Do As Infinity (D.A.I.) was one of the most popular names in Japanese pop music. Several of their songs were used as themes for Japanese television shows, movies, video games, and anime, which gained them a great amount of popularity both in Japan and worldwide. The group disbanded in September 2005 and performed their last live concert at the Nippon Budokan. Each member moved onto other projects. Tomiko Van