Margot Robbie -- NERDGASM On 'Suicide Squad' Set!!! (PHOTO)

Margot Robbie became Harley Quinn Saturday ... and both the real and fictional are really hot.

A photog got this pic of Margot Saturday on the set of "Suicide Squad" in Toronto.

The "Wolf of Wall Street" star is there with co-stars Jared Leto, who plays The Joker, Scott Eastwood, Will Smith, Cara Delevingne, and Ben Affleck.