The actor, who played the 10th Doctor from 2005 to 2010, married his wife Georgia Moffett in 2011.
She is the daughter of Peter Davison, who played the fifth incarnation of the Time Lord from 1981 to 1984.
The pair first met after appearing on the BBC show together in 2008 episode “The Doctor's Daughter”.
Speaking about their relationship on broadcaster Gaby Roslin's podcast, Tennant admitted: "Because Doctor Who had run through my life like a stick of rock, to end up marrying the daughter of one of the doctors, it all felt a bit stupid – there were a lot of things against it."
However, Georgia said she was “very much the driving force” for the pair getting together, stating: “Had I not worked quite so hard, it might not have happened.”
“I very much fell into stalker category, she continued. ”Thank goodness I did though. I just made a decision."
Tennant said he feels he “lucked out” meeting Georgia, adding: “You reach a point of your life when you’re looking for someone and it’s sort of chance which version of that perfect partner ambles along.”
The actor – who has five children with Georgia – most recently played serial killer Dennis Nilsen in ITV drama Des.
While appearing on the series, he explained the reasoning behind his "complicated" decision to quit the long-running CBS sitcom.