Not only did I chat Who but I brought my son with me and David was absolutely brilliant with him. The tenth Doctor was where he started when he began watching and I remember sitting in the make up trailer and Sonny just sidling up to David and asking, ‘How does the sonic screwdriver work?’ And David giving him the most brilliant explanation that literally went on for 15 minutes describing all the different buttons and what they did. Sonny was just so smitten at the end of it, it was fantastic – a really magical moment.
—  Ben Miller, on talking Who with David Tennant on the set of What We Did On Our Holiday