René van Vooren was the Thespian pseudonym of René Sleeswijk Jr., born in the Dutch metropolis Amsterdam on 21 April 1931 as son of theater producer René Sleeswijk Sr.

, a stage name assumed to avoid utter confusion. In the 1950s he worked with several Dutch artists, including Tom Manders. In 1966 he joined the duo which made his name, De Mounties, after the death of the previous straight man, Fred Plevier.