Josh Hartnett says some of his famous ex-girlfriends were "mistakes."

Josh Hartnett

Josh Hartnett

The 'Penny Dreadful' actor, who previously romanced Kirsten Dunst, Amanda Seyfried and Scarlett Johansson, has met "very important people" in his life on film sets, but admits he probably shouldn't have dated all of them.

Asked how dating his co-stars has worked out for him, the 36-year-old heartthrob, who has been in a relationship with British actress Tamsin Egerton for two years, said: "I think it's a respectable way of going about it. I've met very important people in my life doing films. Sometimes that had consequences that were just awful for everybody involved. Some were fantastic all the way through. Everybody makes mistakes dating people they work with."

But Josh insists he has no real regrets.

He explained: "They're whom I'm attracted to. Because I share experiences with them and understand a bit about what they are and what they do. If I were able to go back in time, I don't know if I could have done anything any different."

Despite being in the spotlight for many years, Josh claims fame still makes him uncomfortable.

He told Playboy magazine: "Fame can be a dangerous thing. It can destroy you. I used to put myself in positions where I spoke up when I probably should have been listening. When you're young and have convictions, and fame suddenly gives you a microphone, you think, I'm going to tell everybody how it is."