David Hallyday (born David Michael Benjamin Smet; 14 August 1966) is a French singer/songwriter and amateur sports car racer. He was born in Boulogne-Billancourt and is the son of the French singers Sylvie Vartan and Johnny Hallyday. David Hallyday is a first cousin of actor Michael Vartan. Most famously David writes music for others including a collaboration with his father on the 1999 album Sang pour sang by Johnny Hallyday. He also appeared in the teenage comedy He's My Girl (1987).