Swift was on hand to support her dear friend, and the two were snapped chatting and laughing together like any normal pair of girlfriends.
"We do just really random stuff when we are together," Steinfeld said, of their hangouts away from the cameras. "We just love to kick back, listen to music, watch TV, bake, watch movies and all of that kind of stuff."
And apparently, they have another famous lady to thank for their girl time.
"We met, oh my gosh, like three years ago through our mutual friend Emma Stone," Steinfeld said.
The 16-year-old star walked the red carpet in a gorgeous Spring 2014 Prabal Gurung dress, while the 23-year-old pop princess kept it simple in a floral Reem Acra dress.
"Romeo and Juliet," which also stars Damian Lewis, Ed Westwick, Stellan Skarsgård and Paul Giamatti, hits theaters October 11.