Full article - Ign.com - quotes:
"If you've been pacing in anticipation for the last several weeks, waiting patiently for the BBC to announce who will replace the departing Matt Smith as The Doctor... the wait is over. Or at least, it will be soon. Very soon."
"AV Club reported the news that the BBC will be announcing the new actor this Sunday during a live show with Smith, showrunner Steven Moffat, and host Zoe Ball. The special will air at 7PM UK time (2 PM Eastern, 11 AM Pacific in the States)."
Confirmed by official BBC tweet: