The Northern Irishman had long been expected to take up his customary seat with the Sunbury team, and will line up alongside Jake Hill, Stephen Jelley and Adam Morgan in an expanded four-car line-up of BMW 330e M Sport machinery.
Turkington, who is second on the all-time BTCC winners list, has taken 52 of his 63 race victories with WSR-run cars, 48 of them in BMWs.
