Bart Claessen (Dutch pronunciation: [ˈbɑrt ˈklaːsə(n)]; born 22 January 1980, Asten, Netherlands) is a Dutch dance DJ. He is best known for the Techno songs "On the Move" and "Infected" (both 2001 and as Barthezz), which reached numbers 18 and 25 in the UK Singles Chart respectively. He has released a number of tracks under his own name, most notably "First Light" (2007) and "Madness" (2008).