Whoa! Gigi Hadid was attacked by a rabid fan outside the Max Mara show at Milan Fashion Week Thursday -- and in fact, the guy was a known prankster, Vitalii Sediuk, who's pulled similar tricks with other celebs.

Sediuk's the guy in the dark suit and hat -- he grabs Gigi from behind, while her sister Bella holds her hand to try to pull Gigi away. Supermodel Gigi shows off those famous kicks and frees herself from the dude's arms, then gives him a piece of her mind, yelling at him for being an asshole.

Sediuk has attacked Brad and Angelina, rushed a red carpet to plant a wet one on Will Smith and even rushed the stage at the 2013 Grammys. What a jerk!!