See Anna Kendrick's Amazing Cup Trick from 'Pitch Perfect'

Anna Kendrick is such a good actress that she has already been nominated for an Academy Award in her mid-20's. She's such a good singer that she's starring in the new musical comedy "Pitch Perfect," which saw a limited release last weekend and expands this weekend.

But forget about all that stuff. Just look at what she can do with a cup!

Kendrick showed up on "Late Show with David Letterman" to talk about her movie, and Letterman revealed the part of the movie that he found to be most impressive: a musical number in which Kendrick accompanies herself a capella with a plastic cup.

Apparently Kendrick, who is a Reddit user (as if she needed any more reason for nerds to be in love with her), saw this video one afternoon and decided to learn how to do the same thing. She had perfected it by the time she started "Pitch Perfect," so when the production team found out they naturally wanted to put it in the movie.

Of course Letterman happened to have a plastic cup on hand (from the staff drug test, he joked), and Kendrick performed her skill for the audience. It's awesome. Check it out.