The 28 year old is best known as one half of the singer-songwriting duo WaT, along with his extremely close friend Eiji Wentz. In addition to albums and singles, Teppei and Eiji also host a variety show called Ame ni mo makezu! (Fuji Terebi).
As an actor, Teppei played Hideki Ogata in the Japanese television drama Dragon Zakura. He was nominated for Best Supporting Actor for his portrayal of Ijyuuin in another drama, Iryu.
Teppei went on to take the starring role of Atsushi Otani, in a live action adaptation of the manga Lovely Complex entitled Love*Com: The Movie.
Nakahara Aya - author of Lovely Complex - was so taken with him that Bokura no Ibasho was penned, as a manga biography of Teppei Koike's life to date. It particularly focused upon the period when he left home, then formed WaT.
Teppei hails from Ōsakasayama, in the Osaka Prefecture, Japan, though he's lived in Tokyo since 2002.
He lives alone, but he is usually to be found in the company of Eiji Wentz, including holidaying and spending every Christmas together. Read into that what you will, because I know every L/Light shipper will read tons.
So does Teppei Koike wear the face of L for you? For the cast and audiences to Death Note: The Musical, he most certainly does that.