▁on ▁the ▁N ine ▁Network , ▁it ▁was ▁revealed ▁that ▁the ▁show ▁would ▁be ▁losing ▁a ▁major ▁character ; ▁in ▁a ▁spo iler , ▁it ▁was ▁revealed ▁to ▁be ▁Jim ▁Knight . ▁In ▁May ▁ 2 0 1 8 , ▁it ▁was ▁announced , ▁that ▁Steve ▁Bis ley ▁would ▁be ▁returning ▁for ▁the ▁third ▁season , ▁however , ▁he ▁only ▁appeared ▁in ▁the ▁opening ▁episode . ▁ ▁In ▁April ▁ 2 0 1 9 , ▁it ▁was ▁announced ▁that ▁D ust in ▁Cla re , ▁Kate ▁J enk inson ▁and ▁Rob yn ▁Ne vin ▁would ▁be ▁joining ▁the ▁cast ▁of ▁Doctor ▁Doctor ▁for ▁its ▁fourth ▁season . ▁ ▁Fil ming ▁ ▁The ▁series ▁is ▁fil med ▁on ▁location ▁in ▁M ud ge e , ▁a ▁town ▁in ▁the ▁Central ▁West ▁of ▁New ▁South ▁Wales , ▁while ▁the ▁entire ty ▁of ▁the ▁hospital ▁scenes ▁are ▁shot ▁in ▁the ▁Sydney ▁inner - city ▁sub urb ▁of ▁Ro z elle , ▁which ▁is ▁located ▁in ▁the ▁city ' s ▁inner - west . ▁The ▁film ing ▁of ▁Knight ' s ▁home ▁was ▁shot ▁in ▁Sydney ' s ▁south - west ▁section ▁in ▁the ▁town ▁of ▁Cam den . ▁The ▁regional ▁setting ▁for ▁the ▁series ▁has ▁proved ▁to ▁be ▁benef icial ▁for ▁narr ative ▁and ▁production ▁purposes . ▁It ▁has ▁been ▁stated ▁that ▁in ▁addition ▁to ▁$ 1 0 0 , 0 0 0 ▁worth ▁of ▁support ▁from ▁the ▁Regional ▁Fil ming ▁Fund , ▁the ▁regional ▁setting ▁del ivers ▁a ▁unique ▁authentic ity ▁to ▁the ▁series ▁that