How do i do this shot? BSD

Platform: Adobe Creative Cloud CC (premiere, ae, etc.)

Basically I have a shot that I would want to do practically. The shot should look like one shot, static, and we see a  guy (profile-medium) talking then stops...and smoke gently comes out of his mouth. Now the source of the smoke is not a cigarette in the shot but I could use a cigarette to get the smoke look. My reason for going practical is because I cant find a realistic AE effect and this is a realistic video. So the way I originally wanted to go about it was like this:


Have him stand in the profile and talk until the point that I would cut (between him talking and the smoke), have him stand in the exact same position then have him drag a cig, keep his face in that position and then let the smoke come out. 


Are there any special Adobe techniques to make this as fluid and unnoticeable (the cut) as possible.?
thanks and sorry for the verbosity.
I like your idea. You might be able to make a convincing smoke element to superimpose on your shot like this:


get a black sheet or piece of posterboard
cut a small, mouth-sized hole in the posterboard
paint the actor's lips black
have the actor stand behind the black posterboard, and blow smoke through the hole


The lighting would be pretty tricky. The best bet would be to have a light directly overhead, not on the black posterboard at all. The light would (hopefully) catch the smoke but keep the posterboard exceptionally dark.  It could be darkened more in After Effects when you're superimposing it (probably as a chromakey where the key color is black). In addition, you could create a traveling mask over the shape of the smoke.