  We present the discovery and characterisation of the post-common-envelope
central star system in the planetary nebula PN G283.7$-$05.1. Deep images taken
as part of the POPIPlaN survey indicate that the nebula may possess a bipolar
morphology similar to other post-common-envelope planetary nebulae.
Simultaneous light and radial velocity curve modelling reveals the newly
discovered binary system to comprise a highly-irradiated, M-type main-sequence
star in a 5.9 hour orbit with a hot pre-white-dwarf. The nebular progenitor is
found to have a particularly low mass of around 0.4 M$_\odot$, making PN
G283.7$-$05.1 one of only a handful of candidate planetary nebulae to be the
product of a common-envelope event while still on the red giant branch. Beyond
its low mass, the model temperature, surface gravity and luminosity are all
found to be consistent with the observed stellar and nebular spectra through
comparison with model atmospheres and photoionisation modelling. However, the
high temperature (T$_\mathrm{eff}\sim$95kK) and high luminosity of the central
star of the nebula are not consistent with post-RGB evolutionary tracks.
