The members of Tempura Kidz have danced in front of thousands of strangers at sold-out venues across Japan, including Tokyo's famed Budokan and the Summer Sonic festival. Yet on a Thursday night in a Harajuku office building, the teenage quintet is nervous.

They are giving their first interview with an English-language publication, and the group that moved like seasoned pros as pop star Kyary Pamyu Pamyu's backup dancers in 2012 have never looked more childlike. They sit tensely and smile awkwardly and answer in short sentences. They whisper to one another, testing out answers. Offstage, the young group is out of its element.

Their first commercial single, "One Step," comes out in about a week and formally announces their move from the background to the foreground. The group's members — P-chan (13, the lone boy), Yu-Ka (14), Karin (13), Ao (14) and NaNaHo (14) — formed late last year and released a video for a song titled "Cider Cider." "One Step," though, comes with all the pageantry expected from a proper debut: a physical CD, displays at major music retailers, a tie-in with a children's animated TV show. Tempura Kidz's focus on crisp, well-executed dance moves stands in stark contrast to many other fresh-faced J-pop groups, yet in person they seem as normal as any other Japanese junior high school students.