It's a known fact that actors change things in their everyday life to get into character for a new role, but it appears that Jamie Dornan took this to the next level. 

Dornan, who plays a serial killer on Netflix's "The Fall," shockingly admitted to the LA Times how he prepared himself for his part. 

"The first series, I did do a couple of things to try to get inside [his mind]. On the tube, which is our underground system," Dornan told LA Times. "Can we get arrested for this? Hold on ... this is a really bad reveal: I, like, followed a woman off the train one day to see what it felt like to pursue someone like that."

The former "50 Shades of Grey" star said he followed the woman, lurking in the distance for a few blocks. 

The strategy worked and Dornan told LA Times it helped him understand the compulsion of his character. 

"I'm sort of not proud of myself," Dornan admitted. "But I do honestly think I learned something from it, because I've obviously never done any of that. It was intriguing and interesting to enter that process of 'what are you following her for?' and 'what are you trying to find out?"