  Using the canonical transformation of the order parameter which restores the
Ising symmetry of the Hamiltonian we derive the expression for the Tolman
length as a sum of two terms. One of them is the term generated by the
fluctuations of the order parameter the other one is due to the entropy. The
leading singular behavior of the Tolman length near the critical point is
analyzed. The obtained results are in correspondence with that of M.A.
Anisimov, Phys. Rev. Lett., \textbf{98} 035702 (2007).
