  Several examples of classical superintegrable systems in two-dimensional spac
are shown to possess hidden symmetries leading to their linearization. They are
those determined 50 years ago in [Phys. Lett. 13, 354 (1965)], and the more
recent Tremblay-Turbiner-Winternitz system [J. Phys. A: Math. Theor. 42, 242001
(2009)].
  We conjecture that all classical superintegrable systems in two-dimensional
space have hidden symmetries that make them linearizable.
