The Twin Peaks star told Metro that he was not aware that he was making a "camp classic" when he was shooting the movie opposite Elizabeth Berkley.
"We all went into it with absolute conviction," Maclachlan said.
"Had we gone into it thinking we were making a camp classic we'd have ruined the camp element.
"It had to be taken seriously as we were filming it. Only when it was assembled and I saw it for the first time, I thought, 'Oh boy, this isn't going to be pretty'."
He added: "Everyone has their Showgirls. We remember the great films actors have been in and the rest get forgotten. But occasionally people like to revisit the ones that get swept aside."
Of his thoughts looking back, Maclachlan said: "I went into that film with the best of intentions. [Director] Paul Verhoeven and [writer] Joe Eszterhas were at the top of their game and I trusted they'd deliver something that would be controversial and hard-hitting.
"It turned into something completely different. The fun of it is it's found its own niche in an unexpected way.
"People still get a kick out of it. I remember the experience and kind of laugh at the movie. At the time, the finished film came as a surprise."
Watch the Showgirls movie trailer below: