At the Kennedy Center Honors, Anna Kendrick performed a tune from the 1962 film Two For the Seesaw, in honor of its star, Shirley MacLaine.
Heidi Klum, Anna Kendrick, Zach Braff, Josh Groban, Rob Delaney, Olivia Wilde and Dwayne "The Rock" Johnson all got into it on Twitter. It was a brutal, bitter, no-holds-barred affair.
She says #ItDefiesLogic
Check out her full Instagram.