So apparently Momochi was spotted at the Kouhaku during SMAP’s performance.
The 2ch thread I found this on has already been threadlocked, and the matome sites I went through provided no further evidence. Plus, I think she would’ve been at the Countdown concert in Nakano Sun Plaza. There’s also no mention of it on her blog.
Still, it appears Momochi has learnt how to split her body into two. You’d expect nothing less from Tsugunaga-pro.