As a pop singer in Japan, TiA landed a recording contract when she was 16. She released a single and an album when she was 17, and another single when she was 18. But she started burning out, and by the time she was 27, she quit, tired of rehearsing, traveling and performing.

She moved to Manhattan, intending to find something to do that did not involve music, and rented an apartment in a Harlem brownstone that happened to be next to a church.

Through the wall, the singer — who uses a uniquely spelled single name professionally, TiA, as she did in Japan — could hear the church’s 12-voice gospel choir rehearsing during the week and singing at services on Sundays. The music conveyed the exuberance of exaltation, backed up with electric guitars and keyboards and drums. The effect was magnetic, and eventually she walked in and asked to join the choir, even though she had never sung a note of gospel music.

That was two years ago. She has become so practiced and polished that on Saturday, she will take part in a gospel competition in Newark that draws thousands of singers.