My Keira Knightley impression is pretty spot-on. I’ll tell you how to do it.
1. Open mouth.
2. Part teeth but keep them lined up with each other [thanks, Genny].
3. Tuck tongue just behind bottom teeth.
4. Raise lips until they just clear your teeth. This will give you a bit of a snarl. That’s good.
5. Pull the sides of your mouth into a smile, but keep the snarl aspect of the front of your mouth.
6. Dart eyes from side to side as you widen them as if to say, “I KNOW! Isn’t it AMAZING? Isn’t everything WONDERFUL?!”
7. Inhale and exhale audibly.
8. Say, “It’s fanTAStic!” Let your nose crinkle. Never let your teeth touch.