Late last year, it was announced that the Assassination Classroom anime would be kicking off a trio of special activities for its 10th anniversary. A rebroadcast of all 47 episodes was the first to be revealed. Today, it’s been announced that the rebroadcast will also include brand new openings and endings with new theme songs!
The new opening song will be titled “Kiiro Shingo” (literally “Yellow Light,” localized by the artist as “Caution”) and will be performed by singer-songwriter TOMONARI SORA. This up-and-coming music star has been recognized for his presence in every aspect of the songwriting process—composition, lyrics, arrangement and even the cover art for each track.
Three-member band ATARAYO will perform the new ending theme song, “TSUKI NO FUNE” (“Moon Ship”). In the world of anime, the band previously performed the opening theme “Boku wa…” for season 2 of The Dangers in My Heart.

TOMONARI SORA

ATARAYO
The rebroadcast kicks off on Fuji TV on April 10. Both “Kiiro Shingo” and “TSUKI NO FUNE” will be available digitally starting April 9.
Two more 10th anniversary activities are planned, though what these will be has yet to be announced.

Crunchyroll streams the Assassination Classroom anime and describes the story:
Forget about homework and pop quizzes. The students of Class 3E have a far more important assignment: kill their teacher before the end of the year! A tentacle-d sensei that moves at Mach 20 is out to conquer the classroom after destroying seventy percent of the moon. In addition to reading, writing, and arithmetic, the murderous monster behind the lectern will teach his students everything he knows about the assassination game. Should some eager beaver prove to be a quick study in killing, he or she will save Earth from extinction – and collect a hefty reward.
Source: Official Website