She learned how to turn the cup into a drum on the geek-cool site Reddit (which this editor lives on, truth be told), and when she saw a viral video of a girl singing along with a plastic Solo, she sat down and taught herself how to do the same. (Because, you know, that's what you do when you are an Academy Award nominee and a part of one of the largest franchises Hollywood has ever made.) Obviously, when her Pitch Perfect director heard how she could get all DIY on cup-drums, he incorporated the skill into the movie, immediately.
Seriously though, watch this. It is amazing. Kendrick looks so petite and charming, and delightfully bright in this clip, wearing a stunning yellow dress and with low-key waves, that we almost just did an outfit post on her sunny ensemble on its own. But then she dropped some serious knowledge, showing us her pipes, and earned a rare (and well-deserved) standing ovation from Letterman. Just try to not be impressed. We dare you.
(Side note: After watching this, we caught our deputy editor staring sadly at her own espresso cup, lamenting, "This cup doesn't do anything. Nothing at all." True story. So, watch at your own peril.)