The pair, who appear together in the movie "A Rainy Day in New York", went live on the platform while Chalamet was waiting in line to vote at Madison Square Garden.
Selena, who appeared to be laying down in bed, asked her pal about the voter turnout in the Big Apple during the state's first day of in-person voting, revealing that she voted via a mail-in ballot as she is unable to go in-person this year.
"I really hope this guy loses… oh man. I think in New York we're safe, victory-wise," reflected the actor said while talking about his hope of getting incumbent President Donald Trump out of the White House.
"My stomach hurts because I'm nervous," Selena admitted.
The "Wolves" singer has been active in encouraging fans to vote and has taken part in various livestream benefits alongside Democratic Party figures while urging her followers to back Joe Biden on 3 November (20).
Selena proudly shared Instagram pictures of herself voting early in the 2020 presidential election. "Just finished filling out my ballot," she captioned a photo of herself wearing an "I Voted" sticker.
This year, the former Disney star produced "Living Undocumented" about immigrant families living in the United States.
In an interview with Vogue, she talked about life in Trump's America. "I understand that there have to be rules and regulations, but we have to do better than what we are doing - we simply have to. I hope we can still offer the American dream. I hope we can still offer people a better life. It's so important to remember our country was formed by those who came from other countries," she said.