I just saw her retweet too. There's a page-long article about the new song. Apparently it's "Pray", written by Kunio Tago?
Definitely excited about this. I really can't tell the genre just from the title (I mean, stuff like "is this LOVE?" is a fucking headbanger and "ANGEL'S SONG" is a cutesy upbeat song so I think we're gonna be surprised
) unless it actually says what the song is like in the article (I don't speak Japanese).
I hope it's a good song that gets her to the top.
EDIT
I really _love_ the BUDDHA series by Osamy Tezuka. It's a long-ass set if comic books, but they're really good. I'm very happy that ayu's singing a theme for something in the series.