  To date more than 3500 exoplanets have been discovered orbiting a large
variety of stars. Due to the sensitivity limits of the currently used detection
techniques, these planets populate zones restricted either to the solar
neighbourhood or towards the Galactic bulge. This selection problem prevents us
from unveiling the true Galactic planetary population and is not set to change
for the next two decades. Here we present a new detection method that overcomes
this issue and that will allow us to detect gas giant exoplanets using
gravitational wave astronomy. We show that the Laser Interferometer Space
Antenna (LISA) mission can characterise hundreds of new circumbinary exoplanets
orbiting white dwarf binaries everywhere in our Galaxy - a population of
exoplanets so far completely unprobed - as well as detecting extragalactic
bound exoplanets in the Magellanic Clouds. Such a method is not limited by
stellar activity and, in extremely favourable cases, will allow LISA to detect
super-Earths down to 10 Earth masses.
