Doctor Who: 12 Cool Details Revealed In Steven Moffat's Blink Commentary
8. David Tennant And Freema Agyeman Worked On The Episode For Just Two Days
Blink was Series 3's designated "Doctor-lite" episode, a story designed to include as little of the Doctor as possible. Love & Monsters occupied this slot in Series 2.
These stories were necessary to allow the stars of the show to film multiple episodes simultaneously, making the production of the series that little bit easier.
As a result, David Tennant and Freema Agyeman don't have much heavy lifting to do in Blink, with most of their screen time being limited to the DVD easter egg.
As noted by Moffat, they only worked on the episode for two days. Around the same time Blink was being shot, Tennant and Agyeman were more focused on filming Paul Cornell's Human Nature/The Family of Blood.