EXCLUSIVE: Karissa Shannon Channels Marilyn Monroe at ArcLight

EXCLUSIVE: All decked out in a black lace-lined white dress, the buxom and platinum blonde Karissa Shannon signs autographs for a full frontal assault of fans at ArcLight Theatre.

The sex tape star is a model of poise and concentration dealing with all these demanding guys ... but she does betray a little stress in her facial maneuvers.

It's back to watching those Marilyn films again, dahling!