Marvel and directors Anthony and Joe Russo's Avengers: Endgame is just a mere $8 million away from overtaking James Cameron's Avatar at the worldwide box-office. Now, each and every one of us here on Earth has seen the movie, so there is no need to warn anyone that, at the end of the film, we saw Chris Evans' Captain America travel through time and come back to present day as a happily married old man. And being that we've all seen that scene, today we have a fun fan theory that suggests that it was always Marvel's plan to have Old Man Rogers become - wait for it - Stan Lee.

Not real-life Stan Lee mind you (although that would have been badass) but MCU cameos-galore Stan Lee.

RELATED: Scarlett Johansson Reveals Her Reaction to Black Widow's Endgame Death

Let me explain. While the theory is a bit long in the tooth, the gist of it says that even though Steve goes back in time to live with Peggy Carter - and lays low as to not interfere with the future - he would want to check in on things. And which old man has been in the background of every Marvel movie ever made? Yep, Mr. Stan Lee.

So if this theory holds up, why didn't the Russo Brothers have Stan Lee's Avengers: Endgame cameo be as Old Man Steve then? Well, unfortunately, we lost Stan Lee last year, and the directors probably didn't want to "dishonor his legacy with a CGI clone playing such an important scene" so they had Chris Evans play the role instead.

Let's break it down a bit more. Steve went back in time with Thor's hammer - and those pesky Infinity Stones - with every intent to return them to their proper timeline. So this means he could easily be in all of the off-world locations Stan Lee was, like Sakaar in James Gunn's Guardians of the Galaxy.

And speaking of which, there are some fun Stan Lee-cameos connected to this theory. Such as in Captain America: The Winter Soldier "it makes sense for Steve to want to hang around his exhibit as a guard, telling people about himself discreetly." And in Avengers: Age of Ultron Stan appears as a World War II veteran, just like Steve. In Captain America: Civil War "Tony Stank" is just "Steve playfully jabbing at his old friend." In Guardians of the Galaxy Vol. 2, Steve is telling the watchers "about the great time he's had messing with the Avengers over the years." And in Avengers: Infinity War "Steve has seen plenty of spaceships in his day, really, these kids shouldn't be shocked."

Sure, there are some time-travel issues with this theory, but the author behind it explains how it all works over on Reddit, and you can read through all that time-travel mumbo-jumbo yourself in the link below and take it up with him from there. Basically, he thinks it all works out. What do YOU think? Let us know! This theory comes to us via Reddit.