Back to the Future is one of the most iconic films of all time. But did you ever think anything of the pictures of the four prominent scientists at 1955 Doc Brown’s home? The future inventor of time travel had portraits of Isaac Newton, Benjamin Franklin, Thomas Edison and Albert Einstein hanging on the wall.

And now a stunning new fan theory has argued there was a very specific reason young Doc kept those pictures, aside from sentimental value.

Reddit user theyusedthelamppost argued: “Doc had been thinking about time travel for years prior to 1955. 

“He knew that if he were to ever invent a time machine, he would be tempted to go back and meet these four people. 

“He also realised that doing so would carry a risk of doing something which changed those people.”

READ MORE: Back to the Future: Marty parents PLOT HOLE solved by screenwriter

Aside from reenacting some classic scenes, Gad asked what a Back to the Future 4 would look like.

The 39-year-old said: “Bob and Bob have said there’s never going to be another Back to the Future sequel, which I hope is a lie.

“If hypothetically they were, I would love to hear what you would pitch for Marty and Doc to travel back to and why.”

Producer and co-writer Bob Gale joked: “Well it would have to be that Doc and Marty find out that we’re thinking about making another Back to the Future movie and they come back to stop us from doing such a crazy thing.”

But interestingly director Robert Zemeckis added: “If I had an idea which I could have pitched to Bob with a straight face, we would have made it.

“I have no answer to that question.”

So maybe he’s suggesting that if there had been a good enough idea for Back to the Future 4 that they could both agree on, it would have happened?

However, this hasn’t occurred and the pair have repeatedly said a fourth movie will never happen.