This paper presents a system that takes audio signals of any song sung by a singer as the input and automatically generates a music video clip in which the singer appears to be actually singing the song. Although music video clips have gained the popularity in video streaming services, not all existing songs have corresponding video clips. Given a song sung by a singer, our system generates a singing video clip by reusing existing singing video clips featuring the singer. More specifically, the system retrieves short fragments of singing video clips that include singing voices similar to that in target song, and then concatenates these fragments using a technique of dynamic programming (DP). To achieve this, we propose a method to extract singing scenes from music video clips by combining vocal activity detection (VAD) with mouth aperture detection (MAD). The subjective experimental results demonstrate the effectiveness of our system.