We have discovered a dwarf nova ( DN ) of type SU UMa in Kepler data which is 7.0 arcsec from the G-type exoplanet survey target KIC 4378554 .
The DN appears as a background source in the pixel aperture of the foreground G star .
We extracted only the pixels where the DN is present and observed the source to undergo five outbursts – one a superoutburst – over a timespan of 22 months .
The superoutburst was triggered by a normal outburst , a feature that has been seen in all DNe superoutburst observed by Kepler .
Superhumps during the super outburst had a period of 1.842 \pm 0.004 h and we see a transition from disc-dominated superhump signal to a mix of disc and accretion stream impact .
Predictions of the number of DNe present in Kepler data based on previously published space densities vary from 0.3 to 258 .
An investigation of the background pixels targets would lead to firmer constraints on the space density of DN .