  The star HD 118203, classified as a K0 subgiant, was known to harbour a
transiting hot Jupiter planet on a 6.1-day eccentric orbit. Previous studies
also revealed a linear trend in the radial velocity (RV) domain, indicative of
a companion on a wide orbit. Such a hierarchical orbital architecture could be
helpful in studies of the origins of hot Jupiters. We acquired precise RV
measurements over 17 years using the 9.2 m Hobby-Eberly Telescope and the 3.6 m
Telescopio Nazionale Galileo. Combining these observations with space-born
photometric time series from the Transiting Exoplanet Survey Satellite, we
constructed a two-planetary model for the system. Astrometric observations from
Hipparcos and Gaia were used to constrain the orbital inclination of the
wide-orbit companion and its mass. Numerical simulations were used to
investigate the dynamics of the system. The photometric data were searched for
additional transit-like flux drops. We found that the additional companion is
an 11-Jupiter mass planet orbiting HD 118203 on a 14-year moderately eccentric
orbit, constituting a hierarchical planetary system with the hot Jupiter. Both
planets were found to be dynamically decoupled mainly due to the general
relativistic apsidal precession of the inner planet, marginalising secular
interactions. The orbits of both planets might have a relatively low mutual
inclination unless the longitudes of the ascending node differ substantially.
This configuration favours the coplanar high-eccentricity migration as a path
to the present-day orbital configuration. No other transiting planets with
radii down to 2 Earth radii and orbital periods less than 100 days were found
in the system.
