A new report suggests Marvel Studios has roped in screenwriter David Callaham to write an upcoming and yet to be announced Phase 4 superhero project. Callaham’s credits include 2005’s Doom, The Expendables, Godzilla, Wonder Woman 1984, Mortal Kombat, and Zombieland 2.

As the news has not yet been confirmed, it’s better to take the rumor with a pinch of salt.

According to That Hashtag Show report, Callaham boarded the new project sometime last month. He has already worked with Marvel in the past, having done some uncredited work on Peyton Reed‘s Ant-Man and some of his other projects.

While nothing about the mystery project is known at this point in time, it’s unlikely that the movie in question is Black Panther 2, Black Widow, or The Eternals as all of those projects already have their writing teams attached.

It is speculated that David Callaham could be working on tweaking the script for Doctor Strange 2, which is soon going to start filming, or perhaps the Young Avengers film that Kevin Feige teased a few months ago. Young Avengers is expected to introduce a number of new characters. It’s also possible that The Expendables writer could have been tapped in to pen down the Dark Avengers’ script or work on potential Marvel Studios projects could be sequels such as Ant-Man 3, Captain Marvel 2, or Spider-Man 3.

For now, we will just have to wait to find out more about the mystery project in works.

Callaham’s most recent project Wonder Woman 1984 is currently undergoing filming. Directed by Patty Jenkins, the film is based on a screenplay by Jenkins, Callaham, and Geoff Johns.

Wonder Woman 1984 stars Gal Gadot as Wonder Woman/Diana, Chris Pine as Steve Trevor, Kristen Wiig as Barbara Minerva/Cheetah, Pedro Pascal, Gabriella Wilde, Ravi Patel, and Natasha Rothwell and  Lynda Carter.

Wonder Woman 1984’s release date has been pushed to June 5, 2020.