Let

z_o = 1,           z_2n+1 = - 1,                          z_k = cos ¢_k + i sin ¢_k

z _n+k =z_k         k = 1(1) n

be the vertical projections on unit circle of the zeros of (1-x²) P_n (x), where P_n (x) stands for n^th Legendre polynomial having zeros x_k = cos ¢_k, k = 1(1) n such that 1 > x₁ > … > x_n > - 1. In this paper, we obtain regularity, explicit representation and convergence of mixed type (0, 1, 3)-interpolation on unit circle.