In the movie, Mark plays real life investigative journalist Mike Rezendes - one of the reporters who uncovered a catholic priest pedophile ring dominating Boston and brought the case to light in the Spotlight pages of the Boston Globe newspaper.

It's a difficult tale to tell, but Mark is hopeful that the success of the movie will inspire others to make more movies tackling controversial and sensitive stories that need to be told.

"These kinds of movies ask a little bit more of us and engage us in a different way and I think everyone is a little surprised, I know I was, to have such expansive acceptance and love throughout the world," he said during an interview on British TV show Lorraine on Friday (29Jan16). "Which I think is a good signal that we can keep making more of these kinds of films and actually do well."

Spotlight is also unusual in the way it portrays journalism as a force to be reckoned with. And Mark was keen to be involved in a project that had this view on the media - as he is an "avid fan" of writing done well.

"I see it's importance in the world and I feel like this was a story where we saw where journalism really works at its best," Mark said. "We don't get to see a lot of movies where we get to see journalism actually working. And it's such an important story that I think we as a culture can't be reminded of enough. I read it and immediately had signed on, without hesitation."

To ensure he portrayed Mike correctly, Mark spend a week alongside him, "haranguing him" with questions. While the journalist was slightly uncomfortable with the attention at first, he soon got used to it.

"I don't think he was used to having somebody asking him questions," Mark said. "I think he reserved that for himself. I think it made him a little uncomfortable at first but eventually I think he saw what i was trying to do and it's really to honour him and to honour the survivors of this."