Yaay!
It would be so charming from her to do something like that if it's true. She really likes Lüc and though I don't I'm happy she has him. And I realized that all with the title.
The song is about Lüc and the Yoü part refers to him
I think the idea behind it is adorable, it's something her fans will know but people who don't know anything about her personal life will just scratch their heads at.