'''Heavyshift''' (Sometimes '''Heavy Shift''') is the name of a British acid jazz trio composed of William South (piano) and John Wallace (saxophone) and Julian Fenton (drums), who first met and started gigging together around 1994. They have so far released four albums (The Cocktail Years not officially representing Heavy Shift but rather Wallace/South) . Their debut album, ''Unchain Your Mind'', featured the hit single "90 Degrees in the Shade" and went to the Top Five on the new adult contemporary charts and Billboard jazz charts being named "Album of the Year" by Jazz FM.{{cite web|title =The Conversation: Review |first=Paula |last=Edelstein |publisher=Allmusic| url =

Heavyshift music has been used for various soundtracks including ''Baywatch'' and ''9½ Weeks 2''. A new version of ''Say Hello to Teddy'' (which was released on Jazz FM's label in 2004) is to be taken up by respected US jazz imprint Instinct Records.

South & Wallace have also lent their recording talents to a wide range of individuals, including David Bowie, Tom Jones, All Saints, and James Taylor.