User blog comment:Jkphantom9/OFFICIAL: Japanese Cast Announcement!/@comment-11188061-20150610012252/@comment-11188061-20150610053238

Weiss' VA voiced Akiyama Mio in K-On - which, although the anime/manga itself is cutesy the songs she sing as Mio is quite mature and impressive. She'll probably make a better Blake actually, but I guess they're prepping for the case where Weiss sings in canon.