Abstract. Let G be a locally compact group and let A(G) and B(G) be the Fourier algebra and the Fourier-Stieltjes algebra of G, respectively. For any unitary representation π of G, let Bπ(G) denote the w * -closed linear subspace of B(G) generated by all coefficient functions of π, and B 0 π (G) the closure of Bπ (G) ∩ Ac(G), where Ac(G) consists of all functions in A(G) with compact support. In this paper we present descriptions of B 0 π (G) and its orthogonal complement B s π (G) in Bπ(G), generalizing a recent result of T. Miao. We show that for some classes of locally compact groups G, there is a dichotomy in the sense that for arbitrary π, either B 0and study the question of whether B 0 π (G) = A(G) implies that π weakly contains the regular representation.