Netflix’s Baby Reindeer is haunting. There are episodes in which it was difficult to breathe, and some we could barely keep watching. The show has gripped millions of viewers worldwide thanks to its intense, unflinching and revelatory portrayal of a real-life trauma many of us have never seen on screen. Jessica Gunning plays Martha, Donny’s (Richard Gadd) stalker, in the series. Here she discusses getting into character, that final voicemail message and the distinctive giggle that still echoes in all of our heads.