Sink, 20, revealed she, Brown and their Stranger Things costars are very close friends in real life — so much so that they've played critical roles in helping each other navigate growing up in the spotlight.
"Having each and every kid on the show — I think we'd be so lost without each other," Sink told Access. "We really depend on each other when things get absolutely nuts, or when you need to talk to someone who understands exactly what you're going through. We have each other."
She continued, "Especially having Millie — she was the only girl at first. So, I think, it was nice that we had that connection."
The All Too Well (10 Minute Version) short film actress praised her cast mates for their support, calling their connection "really unique and something I'm so grateful for."
Season 4 of Stranger Things aired two parts this past summer — and the fate of Sink's character, Max Mayfield, remains to be seen. Season 4 ended with Max's near-death battle with the show's leading villain, Vecna (Jamie Campbell Bower). Though Max nearly met the same, brutal fate of many of the Hawkins teens, she was saved by Brown's Eleven.
However, the series ended with Max in a coma after she fell from Vecna's grasp with many broken bones and an inability to see.
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Stranger Things has been renewed for a fifth and final season, which has no release date yet. Seasons 1–4 are streaming on Netflix now.