Lipsync or talent? I suspect the former.

*skillful

Adding video to channels (Skillful) - requested by ant.

How bout now?

Just think about all the great pranks this man could do....

This sort of thing is just a function of knowing what components of vocal tone you can manipulate, how to manipulate them, and engaging in careful, recorded practice until you can routinely reproduce the correct mix. Some vocal strengthening also has to occur over time, much like a singer gradually extending his or her range. The average female voice is only an octave higher in pitch than the average male voice, i.e. a pitch which with practice can easily be reached and maintained by nearly all men. The bigger problem is that men's voices are far more resonant, i.e. rumbly and full, than women's voices. What a man would need to do to reproduce a "girl voice" would be to raise his pitch, and then partially pinch his upper throat and palate, while simultaneously keeping a relaxed throat through which breath can easily flow. If you just pinch the throat without raising pitch, you sound like a nasally drag queen. If you raise the pitch and overly pinch the throat, then you get an artificially thin voice. Merely raising the pitch would just sound like a guy whose voice didn't deepen terribly.

Finally, all of the above would just produce female tone. Much of what we identify as "female" about a voice, isn't tone, but cadence, word choice, and inflection.