If you follow Anna Kendrick on Twitter, then you know that she is one hilarious human being. But she puts all of her improv skills to the test in her new film Happy Christmas, alongside Lena Dunham.

Chelsea Briggs caught up with Anna at the Sundance Film Festival in Park City, Utah to talk about her improv skills, working alongside the talented Lena and what it’s really like to have “Cups” become such a success!

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In Happy Christmas, Anna plays the character of Jenny, who heads to Chicago to stay with her brother Jeff (Joe Swanberg), who is a filmmaker married to his wife Kelly (Melanie Lynsky) and their two-year-old son. Things take a turn when Anna and her friend Carson (Lena Dunham) find out more about Kelly’s life and career, all the while Jenny strikes up a romance with the family’s babysitter (Mark Webber).

Anna may be a talented actress that can be a part of the indie film scene, as well as big studio movies, but she has something under her belt that many at Sundance don’t – a Billboard hit song! Her Pitch Perfect tune “Cups” hit the radio waves and has completely blown up, much to Anna’s surprise. “It’s so weird. It’s the weirdest that has or probably will ever happen to me,” she explained. “Like, it’s just so funny and obviously I’m just blown away and so grateful, but at the same time totally bewildered in the most wonderful way."

Will you be checking out Happy Christmas?