The I Am Legend star was caught offguard when the unnamed Ukrainian journalist grabbed him and tried to land a smooch on the stunned actor before a pre-screening interview.
In video footage of the incident, Smith appears to shove the guy away, saying, ""Hey man, yo man, what the hell is your problem, buddy?""
The angered Hollywood actor then gave the man a light backhanded slap on the face before moving on down the red carpet.
Apologising to his next interviewer, Smith said, ""Hey sorry, he tried to kiss me on the mouth. Joker. He's lucky I didn't sucker punch him!""
The star then brushed off his concerned publicist and continued on with the press line, telling his rep, ""It's all good.""
According to TMZ.com, the Ukrainian reporter has made a name for himself trying to kiss celebrities he interviews.