  The origin of fast radio bursts (FRBs) is currently an open question with
several proposed sources and corresponding mechanisms for their production.
Among them are compact binary coalescences (CBCs) that also generate
gravitational waves (GWs). Spatial and temporal coincidences between GWs and
FRBs have so far been used to search for potential FRB counterparts to GWs from
CBCs. However, such methods suffer from relatively poor sky-localisation of the
GW sources, and similarly poor luminosity distance estimates of both GW and FRB
sources. The expected time delay between the GW and radio emission is also
poorly understood. In this work, we propose an astrophysical scenario that
could potentially provide an unambiguous association between CBCs and FRBs, if
one exists, or unambiguously rule out FRB counterparts to a given CBC GW event.
We demonstrate that, if a CBC that emitted both GWs and FRBs, is
gravitationally lensed, we can make a $> 5\sigma$ association using time-delay
estimates of the lensed GW and FRB images (in strong lensing), which are
expected to be measured with mili-second (for GW) and nano-second (FRB)
precisions. We also demonstrate that the CBC-FRB association can be made in the
microlensing regime as well where wave-optics effects modulate the GW waveform.
We further investigate the rate of such detected associations in future
observing scenarios of both GW and radio detectors.
