Jef Martens known by his stage name Basto, sometimes stylized as Basto!, (born in Hoogstraten, Belgium is a Belgian DJ specializing in Electro House music. He is signed to ARS label. He is also known to have used various aliases like Bitch Boys, Candyman, Dirty Bunch, DJ Basik, Jin Sonic, Kings of Porn and Lazy Jay.
He started DJing in 2005. He found local success in Belgium and Netherlands through Rock With You (2005) and through a cooperation with Peter Luts in On My Own (2008).
However it was with Gregory's Theme in 2011, a song originally written as a classical homage to Hugh Laurie's iconic TV character Gregory, and transformed by Basto into a dance record, that Basto found chart success in France. After some well-received remixes for well-known artists like Kylie Minogue, Moby and Sander Van Doorn, he gained fame through an international dance hit "Again and Again" with chart success in many countries. Notably Basto! dropped the exclamation mark from his name to be known as Basto.