I became a girl group idol for my sister

"Ah, you mean Miyamoto-san, of course he's the world's number one idol!"
"That's right, we will always follow behind Nana-chan!"
"Miyamoto Nana is so awesome!"
This is what fans are talking about.
"Why? Why do my cheeks turn red and my heart beat faster when I'm facing Nana-chan? This isn't love, is it? But that's impossible, Nana-chan is a girl!"
This is the soliloquy of an idol from a girl group.
Miyamoto Nana, a rising star of the girl idol group SKR (Sakura) and the one who is most likely to become the new generation ACE, can form a couple with many members of the group. Facing the enthusiastic fans, she showed a sunny smile, which made more people cheer.
But in fact, she has a secret of her own. The one shining in the girl idol group at this moment is actually him!
He, Miyamoto Nana, whose real name is Miyamoto Sei, is a boy!
And he became an idol in a girl group completely because he was forced!
************************
A more serious introduction: The story of a boy who continues to shine in a girl group. It is a story full of youth, love and passion, really!!!