In the present paper, first we describe the orthogonality relations between denominator polynomials of $[n-1/n]$ Pade approximants and related power series expansion of two parameter function of Mittag--Leffler type; next we compute four orthogonal polynomials which are extracted from numerator as well as denominator polynomials of both even and odd order convergents of the regular $C$-fraction connected to Pade approximants. The two orthogonal polynomials extracted from denominators are shown to be classical orthogonal polynomials and two orthogonal polynomials extracted from numerator are shown to be non-classical orthogonal polynomials.