This Saturday, the countdown to The End of Time begins – not 2012, but the final three adventures of the Tenth Doctor, David Tennant. BBC America premieres The Waters of Mars on Saturday, December 19 at 9pm ET, followed by The End of Time Part One on December 26th and End of Time Part Two on January 2nd. David Tennant is the most popular incarnation of the Doctor since Tom Baker. While we’re sorry to see him go, we’re excited by hints that these specials will give the Time Lord the most glorious send-off ever. Click here to hear him discuss his imminent departure.