The American star has soared to fame thanks to appearing in the Star Trek movies and TV series like Heroes and American Horror Story. Being so successful comes with its pitfalls though, as Zachary admits he longs for more of a challenge in scoring a part like he used to encounter.

“I want to raise the bar for myself, and I am in this interesting spot where I do get offered a lot of things, but frankly, the majority of the things I get offered I'm not really interested in doing,” he sighed to Interview magazine. “I want to do the things that I have to fight for."

"I want to be working with directors who are at the top of their game. I want to be raising the bar for myself, and to me, the best way to do that is to prove to them that I'm the best for this job. I've been looking for ways to audition more, because it also keeps me sharp and keeps my ambition at its firm edge.”

Zachary’s next project certainly kept him on his toes as he stars alongside Joseph Gordon-Levitt in political drama Snowden, about American computer expert Edward Snowden, who leaked classified information from the National Security Agency (NSA) in 2013. The actor plays journalist Glenn Greenwald, who published the secret documents in The Guardian newspaper, and getting an insight into the events gave Zachary a whole new outlook on the time.

“It certainly woke me up to how vulnerable we all are,” he noted. “I think I was much more cavalier about it before I started working on the movie, and then the more I read the documents themselves and saw just how sweeping and indiscriminate the intrusions into our privacy have been, it made me more aware.”