'Stranger Things' Announces Endgame and Supersized Season 4 Premiere Dates

The end is near.

On Thursday, Netflix announced that Stranger Things will end after season 5 — but not before its highly-anticipated season 4 premiere, which will now be expanded into two parts.

In an open letter to fans, series creators Matt and Ross Duffer explained their decision to split up season 4 and why the time has come to end the series.

"Seven years ago, we planned out the complete story arc for Stranger Things. At the time, we predicted the story would last four to five seasons," they wrote. "It proved too large to tell in four, but – as you'll soon see for yourselves – we are now hurling toward our finale."

They confirmed that "Season 4 will be the penultimate season; season 5 will be the last."

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But fans can temporarily rest easy — season 4's runtime will nearly double any of the previous seasons, making it a supersized event. The Duffer brothers explained that with so much content, the season will be broken into two parts, with two separate summer premieres. The first half will air on May 27, while the second half will come on July 1.

"With nine scripts, over eight-hundred pages, almost two years of filming, thousands of visual effects shots, and a runtime nearly twice the length of any previous season, Stranger Things 4 was the most challenging season yet," the brothers wrote. "But also the most rewarding one. Everyone involved is incredibly proud of the results, and we can't wait to share it with you."

The news comes just a day after Netflix teased the return of the series in a cryptic billboard posted in Los Angeles, California. The billboard showed upside-down text that read, "Every ending has a beginning."

Aside from assumptions that the billboard was directly related to Netflix's hit thriller series, there were a few concrete clues. The Stranger Things Twitter account responded directly to the billboard with a cryptic tweet of their own: an upside-down smiley face.

While details on what to expect for season 4 have been sparse, Noah Schnapp, who plays Will Byers in the series, previously told PEOPLE that the upcoming season will be "unexpected, romantic and exhilarating." "I think this season is going to be the best one yet. It's something to be excited about," he said.

Schnapp, 17, also teased new connections between characters. "Every season we have different storylines and different people that I get to work with. I think this season, it was the most unexpected,'' he continued. "[There were] certain people I'd never worked with before. It just really opened my eyes and I had such a good time doing it."

In November, Netflix dropped a teaser trailer for the upcoming season, sharing a closer look at Eleven's (Millie Bobby Brown) life in California.

"Dear Mike," Eleven said in a letter to love interest Mike Wheeler, played by Finn Wolfhard. "Today is day 185. I think I have finally adapted. I even like school now. I have made lots of friends. Even so, I am ready for spring break, mostly because I get to see you."

As her letter to Mike narrated the clip, Eleven is shown struggling to adjust to her new setting. Aside from Will Byers (Noah Schnapp), she is seen having trouble making new friends — and some of her classmates are seen chucking a spitball her way.

"We will have the best spring break ever," she added.

Part one of Stranger Things season 4 will premiere on Netflix on May 27.