Millie Bobby Brown and Noah Schnapp have been 'best friends' since 'Stranger Things.' Here's a timeline of their friendship.

Back in 2015, Brown and Schnapp met while filming the first season of "Stranger Things." While their characters Eleven and Will Byers don't spend much on-screen time together that season, the duo appeared in photos from the set, accompanied by Finn Wolfhard, Caleb McLaughlin, Gaten Matarazzo, and other members of the cast

On December 16, 2016, Schnapp shared a photo on his Instagram account of him, Brown, Wolfhard, McLaughlin, and Matarazzo, along with the caption, "Day one here we go."

Brown and Schnapp both attended the series premiere of "Stranger Things" in July 2016, posing on the red carpet with their costars.

Brown and Schnapp both attended various awards shows together following the premiere of "Stranger Things" season one, including the 2017 Golden Globes, the 2017 Screen Actors Guild Awards (where the "Stranger Things" cast won the award for Outstanding Performance by an Ensemble in a Drama Series), and the 2017 MTV Movie and TV Awards.

Brown and Schnapp attended the event along with other members of the 'Stranger Things" cast.

Schnapp and Brown posed with Matarazzo, McLaughlin, Wolfhard, and season two addition Sadie Sink on the red carpet.

On July 17, 2018, Noah Schnapp posted a video of him and Brown dancing to Drake's "In My Feelings" on his Instagram account.

"night shoots @milliebobbybrown @champagnepapi," he wrote in the post's caption.

In a since-removed Instagram post, Millie Bobby Brown shared a photo of her and her "Stranger Things" castmates in Halloween costumes. While Brown was dressed as Princess Leia from the "Star Wars" franchise, Schnapp was dressed as a season one version of Eleven, Brown's character from "Stranger Things," Teen Vogue reported.

Schnapp held up the tulle train on Schnapp's dress at the premiere, as the two appeared on the red carpet together.

In August 2019, Schnapp uploaded a video to his personal YouTube channel of him and Brown doing a "best friend challenge." In the video, the pair made guesses about each others' preferences and other personal details, checking to see how well they knew each other.

Brown and Schnapp posed together at the 2020 Screen Actors Guild Awards in Los Angeles. The next day, Schnapp posted a photo from what appeared to be the Netflix afterparty following the event.

"name a more elite duo... i'll wait," he captioned the photo, which showed him and Brown posing against a teal and gold backdrop.

In an October 2021 interview with People, Schnapp recounted a prank Brown had pulled on him during their last day on the "Stranger Things" season four set.

"On our last day of filming season four, Millie, she got the whole crew together and she bought like, 2000 water balloons," Schnapp told the publication. "She called me back to our base camp to hug her goodbye. I got there and I was like, 'Where is she at? Let me go say goodbye.'

"Her and 30 other crew members came out behind the trailers with each like, 100 water balloons, just chucking them at me," he continued.

Brown would later recount the same story on "The Tonight Show Starring Jimmy Fallon," adding that she faked crying while on the phone with Schnapp to convince him to come back to camp.

To celebrate Brown's 18th birthday, Schnapp attended her birthday party, posting a "photo dump" on Instagram after the fact. Photos showed the two dancing together, and Brown appearing to cry as Schnapp gave a speech.

On "The Tonight Show Starring Jimmy Fallon," Schnapp said that he cried when he read Matt and Ross Duffer's letter announcing that "Stranger Things" would end after its fifth season. When he texted Brown, he said, she was crying as well.

"I texted Millie, my castmate who plays Eleven, and she was like, 'You're crying too? So am I,'" Schnapp said.

Appearing on "The Tonight Show with Jimmy Fallon," Brown shared multiple anecdotes from her friendship with Noah Schnapp.

She told Fallon that she and Schnapp would imitate conversations between his "Stranger Things" character Will and his mother Joyce, played by Winona Ryder. While Noah would imitate his younger self, saying that he was trapped in the Upside Down, Brown would imitate Ryder, saying things like, "Come on baby, I am here, I am coming to find you, honey."

Finally, Brown said that she and Schnapp would "race each other with Fruit by the Foot," a lengthy fruit snack. According to Brown, nobody else on set would respond to their challenge.

Schnapp posted a brief clip on June 13 that showed his and Brown's Fruit by the Foot races, along with other behind-the-scenes clips.

At the "Stranger Things" season four premiere in New York City, Schnapp and Brown posed together on the red carpet, hugging while among their other costars.

In a May 27 post, Schnapp shared a video of Brown laughing before a take on set, accompanied by the caption, "She can't keep it together." The video was interspersed with other photos from filming.

In another Instagram post uploaded on June 1, Schnapp included a video of him and Brown dancing together again on set, this time dancing to a remix of "Oh Nanana" by dj 6rb, Bonde R300, XANG, and Mayklove.

A TikTok that Schnapp posted in June shows him and Brown laughing uncontrollably while sitting in chairs in front of a blue screen. At one point in the video, an offscreen voice says that the pair should "run up and down the hall" for a moment.

"Millie and I are clearly experts in press," the caption reads.

Schnapp shared photos on Instagram showing him posing with Bongiovi at the concert, as well as a photo of Brown closing her eyes and grinning widely.

"Big @harrystyles fans," he captioned the post.

Schnapp joined Brown on "The Tonight Show Starring Jimmy Fallon" in October while she was promoting "Enola Holmes 2." The pair played a confessions game with Fallon on the show, where they had to guess whether their confessions were true.

Schnapp and Brown also appeared in Fallon's BeReal the day that they appeared on the show. Schnapp reposted the image on Instagram on October 27.