The Newsroom actress, who also stars in the Steven Soderbergh film, said that she enjoyed watching the actors dance for their roles as strippers.
"I came to set when I wasn't even on the sheet that day to come in," Munn told Access Hollywood.
"I'd come in specifically - I'd go out of my way and cancel all other stuff just to go in and watch them dance and then I would rate them," she added.
Munn went on to admit that her behaviour became unhealthy by the end of the shoot.
"But I'm going to tell you that you can go see the movie and then you can [rate them] yourself," she said. "I just got to see it up close, which, after a while, you just become dizzy and then you're - it's not healthy to do it as much as I did it."
Magic Mike opens in the US on June 29 and July 11 in the UK.
Watch the red band Magic Mike trailer below: