New theme song for MLP Japan starting in July. "Majikaru Dai☆Dai☆Dai-Bōken!" (Big Big Big Magical Adventure!) sung by Nanamori-chu☆Gorakubu.
There's no way to tell before hearing the lyrics, but the title at least makes it seem possible that the song will be show-relevant.
At around the same time, the CD this is included in was announced for a July 31st release date, composed of a group from the Yuruyuri anime. Google Translate:
Be released on the 31st of CD7 month Nanamori ☆ Goraku section, new song! The title "Magical large ☆ ☆ large great adventure! This piece "is the opening theme from July of magic ~" and "My Little Pony Friends ~ anime being broadcast by TV Tokyo addition NOW!
I'm sure it will be up on YouTube eventually! Keep an eye out.