Back to the Future Part III - the final installment of the iconic movie series - was released 30 years ago, but it hasn't stopped folks from dreaming of a fourth film.

We're in an era where Hollywood is rebooting or continuing a plethora of classic movies and film series, after all, so it's easy to understand why Back to the Future fans remain hopeful on a fourth installment.

But once again, BTTF director Robert Zemeckis and writer Bob Gale are emphasizing that a fourth film simply won't happen. This time, they did so during a Back to the Future reunion that was hosted by Josh Gad.

The reunion also included Michael J. Fox (Marty McFly), Christopher Lloyd ("Doc" Emmett Brown) and Lea Thompson (Lorraine Baines-McFly). During the chat, Gad asked what a fourth film could look like.

That's when Zemeckis and Gale once again stressed that they won't be doing a fourth film in the series.

"It would have to be that Doc and Marty find out that we're thinking about making another Back to the Future, and they come back to stop us from doing such a crazy thing," Gale said, via Zach Seemayer of Entertaiment Tonight.

"If I had an idea that I could have pitched to Bob with a straight face, we would have made it," Zemeckis added.

So there you have it. The series director and writer aren't keen on doing a fourth film, so unless Back to the Future is rebooted (anything is possible in the film industry these days), fans will simply have to learn to be content with the trilogy.

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Even if Zemeckis and Gale were keen on a fourth franchise, they'd have to work around a complicated plot and storyline. Back to the Future Part III provided nice closure for Doc and Marty, so what could they possibly come up with for the characters three decades later?

Ask Jerry Seinfeld and the cast of his '90s sitcom series about this, and they'll simply point out how it's important to "leave on a high note" and to leave the audience wanting more. Zemeckis, Gale and the BTTF cast did just that.

Back to the Future has gone down as one of the greatest series in cinema history, and Gale and Zemeckis have good reason to keep it as a trilogy. The legacy of the Back to the Future is already cemented, and it needs no tinkering whatsoever.

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