In February 2014, the Doctor Who team filmed at Mermaid Quay in Cardiff.
The internet then turned it into a series of GIFs...
As if that wasn't enough to make you well up, the little girl's auntie went online to explain the situation...
Oh, Peter Capaldi, you wonderful, wonderful man...
More info on the whole story can be found on the family's blog. Doctor Who returns in Autumn 2014.