Just like Gackt, who was the guest star on last year's blockbuster film, Kamen Rider Decade: All Riders vs. DaiShocker, SOPHIA member, Matsuoka Mitsuru who guest stars in the film as Daido Katsumi/Kamen Rider Eternal will sing the theme song of the upcoming Kamen Rider W film, Kamen Rider W Forever: A to Z/The Gaia Memories of Fate.
The title of the song is obviously called, W (Double) and the single will be released on August 11th.
Source: Livedoor via alternate-zer0