  Recent photometric space missions, such as CoRoT and Kepler revealed that
many RR Lyrae stars pulsate -- beyond their main radial pulsation mode -- in
low amplitude modes. Space data seem to indicate a clear trend, namely overtone
(RRc) stars and modulated fundamental (RRab) RR Lyrae stars ubiquitously show
additional modes, while non-Blazhko RRab stars never do. Two Kepler stars (V350
Lyr and KIC 7021124), however, apparently seemed to break this rule: they were
classified as non-Blazhko RRab stars showing additional modes. We processed
Kepler pixel photometric data of these stars. We detected small amplitude, but
significant Blazhko effect for both stars by using the resulted light curves
and O$-$C diagrams. This finding strengthens the apparent connection between
the Blazhko effect and the excitation of additional modes. In addition, it
yields a potential tool for detecting Blazhko stars through the additional
frequency patterns even if we have only short but accurate time series
observations. V350 Lyr shows the smallest amplitude multiperiodic Blazhko
effect ever detected.
