  Among the perovskite oxide family, KTaO$_3$ (KTO) has recently attracted
considerable interest as a possible system for the realization of the Rashba
effect. In this work, we improvise a novel conducting interface by juxtaposing
KTO with another insulator, namely LaVO$_3$ (LVO) and report planar Hall effect
(PHE) and anisotropic magnetoresistance (AMR) measurements. This interface
exhibits a signature of strong spin-orbit coupling. Our experimental
observation of two fold AMR at low magnetic fields can be intuitively
understood using a phenomenological theory for a Rashba spin-split system. At
high fields ($\sim$8 T), we see a two fold to four fold transition in the AMR
that could not be explained using only Rashba spin-split energy spectra. We
speculate that it might be generated through an intricate process arising from
the interplay between strong spin-orbit coupling, broken inversion symmetery,
relativistic conduction electron and possible uncompensated localized vanadium
spins.
