The 20-year-old actress was decked out in TopShop from head-to-toe for the premiere. The two also stopped by the after-party held at Forty Four at Royalton.
Coriolanus is an action/drama about a banished Roman hero (Ralph Fiennes) who allies with a sworn enemy to take his revenge on the city.
The flick opens on Friday, January 20th.
FYI: Kelsey and William costar in the upcoming Run.