Following the passing on Monday of Stan Lee, director Josh Trank admits he let down the Marvel Comics legends with 2015's Fantastic Four.

Lee and Jack Kirby introduced Mister Fantastic, the Invisible Woman, Thing and the Human Torch in 1961, in the process giving birth to the Marvel Universe. Although the characters loom large in comics, their relationship with Hollywood has been rocky, to say the least. That continued with Fox's 2015 movie reboot, which was met with negative reviews, and lost an estimated $100 million for the studio.

Trank, who directed and co-wrote the film, shared a heartfelt tribute to Lee on Twitter, and revealed a note the legendary creator sent him following the film's release. "Though you could say I let him down," Trank said, "Stan Lee kept in touch."

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"Today we say goodbye to one of the greatest creative icons in history, someone who always reminded us his humanity was not a secret identity," he continued. "Rest in peace, Stan."

The Fantastic Four met with middling success with Tim Story's 2005 film Fantastic Four and its 2008 sequel, Rise of the Silver Surfer. However, fans weren't prepared for the disastrous series of events that led to Fantastic Four's 2015 theatrical release. Trank, who was described as "erratic" and "very isolated" during the film's production, famously attempted to distance himself from the final product.

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Trank's correspondence with Lee refers to what happened with Fantastic Four and the consensus that the movie failed to do justice to the team. Even at age 92, when the movie came out, Lee spoke out against those who criticized the casting of Michael B. Jordan as the Human Torch. He also joked with Larry King that Trank's movie flopped because it didn't include the classic Stan Lee cameo.

Although there were once plans to continue with a Fantastic Four sequel — and Tim Miller even wanted to include the cast in Deadpool 2 — it looks like Disney's acquisition of Fox will ultimately result in another reboot of the property.