The already massive cast of "Avengers 4" has just grown by one. Ty Simpkins, who played Harley Keener in "Iron Man 3," is reportedly reprising his role in the yet-to-be-titled "Avengers" installment.

For those who forgot Harley Keener, he was the tech-obsessed, bullied little boy who warmed Tony Stark's (Robert Downey Jr.) arc reactor-powered heart after he crashed in rural Tennessee. After helping the Avenger repair his armor to fight the Mandarin (Guy Pearce), Harley has never been seen or referenced again, even in the succeeding films that featured Iron Man. However, it looks like Marvel is not done with the character yet if the new casting update is to be believed.

IMDb recently announced in a surprising tweet that "Avengers 4" has added the now-16-year-old actor to the cast. No other specifics were given. Nonetheless, knowing that someone who has shared a brief history with the genius, billionaire, playboy, and philanthropist will be brought back to the fold is interesting, to say the least.

The studio is no stranger to bringing supporting "Iron Man" characters to other franchises. Pepper Potts (Gwyneth Paltrow) and Happy Hogan (Jon Favreau), for example, appeared in the "Spider-Man: Homecoming." But many are wondering what a teenage kid like Harley could contribute to one of Marvel's biggest, star-studded films.

Of course, nothing has been officially confirmed yet, so it is best to take this news with a grain of salt. However, if the report turns out to be accurate, chances are Keener will have a significant role, considering how integral his purpose was in his last appearance in the MCU.

As Slashfilm explained, he could provide Tony Stark some growth, now that the character has no more sequels of his own in the pipeline. If not, he might bring a grim development to the Avenger; Simpkins' return might have something to do with Stark's demise.

A previous casting call looking for mourners suggested a superhero would die in "Avengers 4." With past rumors also claiming the kid from Tennessee could replace Stark in the suit, some are convinced he might attend his funeral and eventually become the new Iron Man. After all, Downey Jr. has long expressed his desire to retire from the MCU before it becomes embarrassing. So, this theory is quite plausible too.

Unfortunately, these are all speculations for now. Simpkins could just end up doing a "blink and you will miss it" cameo. Fans will have to wait to find out.

"Avengers 4" premieres on May 3, 2019.