  We report the discovery of an eclipsing binary star (KIC 7025851) near KOI
565 (KIC 7025846) based on photometric observations of KOI 565 and several
nearby stars acquired in two narrow bandpasses (790.2 and 794.3\pm2.0 nm)
nearly-simultaneously with the GTC/OSIRIS. We use the individual photometry in
each bandpass as well as the colors of KOI 565 and other nearby stars to
determine that the source of the transit signal initially detected by Kepler is
not due to a super-Earth-size planet around KOI 565. Instead, we find the
source to be a background eclipsing binary star located \sim15 arcsec to the
North of KOI 565. We discuss future prospects for using high-precision
multi-color photometry from the GTC to determine whether additional Kepler
planet candidates have a planetary nature or are instead false positives (e.g.,
foreground or background eclipsing binaries or hierarchical triple systems).
Our approach is complementary to multi-color follow-up observations of Kepler
planet candidates currently being conducted with the Spitzer space telescope in
the infrared as well as to other follow-up techniques.
