Sekai no Owari is one of the most popular groups in Japan right now. The clown-faced, top hat-wearing rock band is managing to thrive in a Japanese music industry saturated with seemingly endless three-letter-48-style girl groups.
So what better to combine with one of the most popular music groups than one of the most popular manga/anime, Attack on Titan? It was just recently announced that the upcoming live-action Attack on Titan movies will feature two original Sekai no Owari songs produced specially as theme songs for the films.