UPDATED Iikubo made the announcement in a blogpost.
Titled Haruiro, the photobook will release on January 28. It will consist of 80 pages and include a making DVD with a runtime of 25 minutes. Retail price will be 3.000 yen. The publisher is Odyssey.
It will be available at H!P shops, concert venues and through e-LineUP! Mall.
The photobook will come with a bonus photo out of the selection below: