Born in Newport, 26-year-old Doidge spent time in both Southampton’s and Bristol Rovers’ youth academies, before making his name in the football league with Forest Green Rovers.
During the 2017/18 campaign in League Two, he found the back of the net 25 times in all competitions for Forest Green, whilst in the current campaign he has scored four goals in five appearances.
Manager Phil Parkinson added: “We are delighted with the signing of Christian Doidge.
He’s a player who came into league football quite late and has met every challenge put in front of him.
"He’s someone who fits our profile of what we want in a player and he has the hunger and desire to be the best he can.
“Ken and Lee have worked very hard behind the scenes over a number of weeks to make this deal happen.
"It’s never easy to sign strikers as clubs are reluctant to let them go but their persistence has paid off and we are delighted."