The famous k-pop idol V from BTS isn’t called V in Japan. Actually, he’s called TaeTae.
It is difficult pronounce the letter ‘V’ in Japanese, so they started to call him “TaeTae” because his real name is Kim Tae Hyung. And TaeTae was his nickname on High School.
As a curious fact, in a Japanese show the interviewer asked a married couple to write the favorite thing of the wife. She wrote bread, but his husband wrote “BTS Tae Tae”
Q. What is wife’s favorite thing?
Husband: BTS Tae Tae
— 𝑎𝑖𝑐𝑎 (@verykth) December 29, 2019
TaeTae is the unofficial name for V, but he introduces himself as TaeTae too. Just like Jungkook, that introduces himself as Guku (because the last part of his name is pronounced like “Jung-Guku” in Japan)