Zoe Ball served as host for the special 30-minute show dedicated exclusively to the revelation of the new doctor.
According to the BBC, the audience peaked at 6.9 million and the show was seen by 30 percent of people watching TV at the time.
But in spite its high ratings, the unveiling received generally negative reviews by critics.
"[The show was] less a casting announcement than a global product launch," said The Telegraph's Robert Colvile, "an exercise in brand-management equivalent to the unveiling of the latest iPhone."
"Twentyfive excruciating minutes of teasing involving a Doctor Who nostalgia fest presented by Zoe Ball, that played out like a segment of Live & Kicking," wrote The Independent.
"Presenter Zoe Ball demonstrated why we never see her on mainstream TV anymore, giving a display of such gushing inanity she made Claudia Winkleman look like Sylvia Plath, even introducing 'our very special guest - the Tardis,'" said the Daily Mail's Jim Shelley.
Capaldi, a Glasgow-born self-proclaimed lifelong Doctor Who fan, will replace Matt Smith as the famous doctor. He is the oldest actor to play the role since the first Doctor, William Hartnell, in 1963.