13 Reasons Why star Katherine Langford joins Avengers 4

13 Reasons Why star Katherine Langford is joining the MCU. Photo / Getty Images

13 Reasons Why star Katherine Langford is joining the Marvel Cinematic Universe with the actress landing a role in the highly-anticipated Avengers 4.

While Marvel Studios hasn't confirmed the casting, The Wrap reports that the actress has already shot her scenes.

Principal photography wrapped in January, but the cast and crew reconvened for reshoots last month, which may have been when her scenes were filmed.

She joins a massive ensemble cast that includes MCU heroes such as Tony Stark (Robert Downey Jr.), Steve Rogers (Chris Evans), Thor (Chris Hemsworth), Hulk (Mark Ruffalo), Black Widow (Scarlet Johansson) and many more.

There is no indication yet if Langford's mystery character has any roots in Marvel Comics lore, or if it's a new character unconnected to the comics, the DailyMail reports.

Avengers 4, which still doesn't have an official title and has lead to plenty of speculation and rumors, will be the last movie in Marvel's Phase 3, and it's possible Langford's character could return in Phase 4 at some point.

Avengers 4 will pick up right where this year's Avengers: Infinity War left off, after the nefarious Thanos (Josh Brolin) acquired all six Infinity Stones and snapped his fingers, wiping out half of Earth's population.

Among those killed by Thanos' snap were beloved characters like Spider-Man (Tom Holland) and Black Panther (Chadwick Boseman).

However, with Spider-Man and Black Panther sequels already in the works, most fans are under the assumption that these characters will come back to life, somehow, in Avengers 4.

Marvel has set a May 3, 2019 release date for Avengers 4, with Marvel Phase 4 getting started just a few months later.

The first Marvel Phase 4 movie, Spider-Man: Far From Home, a follow-up to last year's Spider-Man: Homecoming, will hit theaters on July 5, 2019.

The rest of Marvel's Phase 4 slate beyond that is shrouded in mystery, and there is no indication when Marvel will announce the rest of their slate.

After appearing in just three short films, 22-year-old Langford burst onto the scene after landing the role of Hannah Parker in Netflix's beloved series 13 Reasons Why.

She returned for the second season of the hit show, but she will not return for the third season, slated to debut on the streaming service in 2019.

The actress is going back to work for Netflix on another series though, starring as the lead character Nimue on the new series Cursed, which puts a different spin on the King Arthur legend, told through the eyes of teenage heroine Nimue.