Cut Points and How To Direct Them
Let's talk about CUT POINTS.
When you're directing a comedy 'bit' that requires some manoeuvring like this hair cut / wig reveal, you're usually relying on the edit for not only comedy, but ensuring you can 'cover' the one-time fake-hair-snip, or the trickery involved with wig on/offing (similar to this costume reveal moment from Trying).
In this HIMYF scene, the comedy and reveals are all based on cut/edit points, and framing around the tricky bits.
1. OTS shot with a mirror reflecting Ellen's face frames OUT the wig/fake-hair-extensions. This means always having something to cut to between Ellen and Charlie's hair snips (0:06 and 0:21, respectively) and cutting to the actual snip moment helps hide the fake hair's fakeness.
2. When Ellen takes off her wig, she ducks down and begins to take off the wig while in a wide 3-shot, then as she begins to stand at 0:46 there's a cut to the closer, sixty-degree-different-angle 2-shot:
Ellen’s motion of standing and removing the wig continues through, but clearly in the closer shot her hair has been styled beforehand and she's just holding the wig closely front of her head, so when she stands: voila!
A reveal of a perfectly horrible haircut, best styled for horror.