SPOILER-- Series 4-- Don't Read if you Don't Want to Know--

The Timelord is apparently set to get a huge shock when Doctor Who returns this spring - when he discovers he's a dad.
The Doctor, played by 36-year-old David Tennant, is left stunned after he lands on Earth and learns he has a daughter, reports the Daily Star.
But, as with all the sci-fi hit's best storylines, there's a twist and the Doctor finds out the girl has been made by aliens, who sneakily took some of his DNA without him knowing.
The Timelord's daughter is apparently played by 23-year-old Georgia Moffett, who also happens to be the real life daughter of former Doctor Who star Peter Davison, 56.
A source was quoted as saying: "It's an amazing signing!"
More incredible storylines have apparently been concocted for the new series, including a showdown with the Daleks and their evil creator Davros.
Meanwhile, Catherine Tate is set to reprise her role as Donna, the runaway bride, and will star as The Doctor's companion throughout the new series.