According to the official website, an animation PV will be bundled with a new character song of Yoko Littner
("Tengen Toppa Gurren Lagann
") titled "S.t.a.r.S". It will be released on May 27th.
The BOX set "Kirameki★Yoko BOX -PIECES of SWEET STARS-" also has 132 pages of fanbook including the key animations and the continuity of the PV. Nishigori Atsushi, the character designer of Gurren Lagan, directs the new animation.
Source: Official Website of the BOX Set