We study the correlation function of two circular Wilson loops at strong coupling in N=4 super Yang-Mills theory. Using the AdS/CFT correspondence, the problem maps to finding the minimal surface between two circles defined on the boundary of AdS, and the fluctuations around the classical solution in AdS_5 x S^5. At the classical level, we derive the string solution in H_3 x S^1 explicitly, and focus on properties such as stability and phase transition. Furthermore, a computation of the associated algebraic curve is given. At the quantum level, the one-loop partition function is constructed by introducing quadratic bosonic and fermionic fluctuations around the classical solution, embedded in AdS_5 x S^5. We find an analytic, formal expression for the partition function in terms of an infinite product by employing the Gelfand-Yaglom method and supersymmetric regularization. We regulate the expression and evaluate the partition function numerically.