The brunette beauty hits the big screen in the forthcoming sci-fi production and insists filming scenes with the titular monster were different to previous work.
She explained: "I got someone a megaphone saying Monster 1 Monster 2 and then Lizzie and then you turn around and you're like 'Oh that's my action shot'. It was more technical than I thought."
The 25-year-old actress, who plays Elle Brody, insists the adventure goes back to its "roots" which is faithful to the Japanese Toho series.
Olsen said: "This film really roots it back to the reason it was created. A very much so political voice for Japan in 1934 post World War 2 and it's going back to that kind of conspiracy theory. But it's so much fun and I get to play a mother and military wife and a nurse - being a good caretaker."
Although she hasn't seen it in 3D Olsen insists those kinds of films used to be "harmful" to her eyes.
Talking on the 'Late Show with David Letterman', she said: "I haven't seen it in that way yet [3D iMax]."
Show host David exclaimed: "That's the way to see it for God's sake."
Olsen replied: "3D used to give me a headache and I think they figured something out somewhere where it's actually really fun and not so harmful for your eyes."