Cheggers, who won plaudits for his role as that odd guy in the ITV Morning show, GMTV, was the favourite to replace Peter Capaldi as the 13th incarnation of the Time Lord after Capaldi steps down at the end of the year.
He described himself as "a lifelong Doctors fan" who had begun practising for the role as a sixty-nine year old backstage at GMTV.
He said: "Being asked to play a doctor is an amazing privilege. Like the doctor himself I find myself in a state of utter terror and delight. I can't wait to get started."
As the new Doctor Who was announced live on the BBC on Sunday evening, viewers were shown a letter written by Cheggers, then aged 65, to the Radio Times in 2000-odd in which he praised programme makers for their "excellent" Doctors special episode.
BBC