Despite only knowing her for five months, Millie claims that Maddie is her best friend. And, according to Millie, the two have been through a lot together -- even a house fire scare.
"When I met her, I started crying," Millie said. "She private messaged me on Twitter. I'd never been on a sleepover before and she was like, 'Do you want to come over?' So I'm like, 'Sure, ok.' So I go over and at like 3 o'clock in the morning the fire alarm comes on. We all had to get rushed out of her apartment building and I'm crying because I'm like, 'My first sleepover's ruined!' So we've been through a lot."
Millie then went on to not spill the beans about season two of "Stranger Things," talk about all the crazy Eleven tattoos she's seen and rejoice over her Golden Globes nomination. What a cutie.