The tenor - known as The Voice - will perform 13 dates this summer, starting in Glasgow on June 9.
He underwent emergency brain surgery to remove a second tumour last October, followed by five weeks of radiotherapy.
Medics initially feared his voice would be damaged when they were forced to operate via his mouth due to the presence of scar tissue in his nose from a previous tumour.
The 41-year-old is preparing for the tour by attending a gym near his family home in Wilmslow, Cheshire, reports The Mirror.
He indicated on his website that a new album was in the pipeline, saying: "There are all kinds of other plans afoot that I don't think I can reveal yet. Album (cough)."
Watson also revealed that he is writing a book "to set the record straight and say my piece on a couple of things".