While filming his final movie “Night At The Museum: Secret of the Tomb,” Robin Williams was “crumbling,” according to the movie’s director Shaun Levy.

“I would say a month into the shoot, it was clear to me — it was clear to all of us on that set — that something was going on with Robin,” Levy told Entertainment Tonight ahead of the release of “Robin’s Wish,” a documentary that chronicles Williams’ final months.

“We saw that Robin was struggling in a way that he hadn’t before to remember lines and to combine the right words with the performance,” Levy said. “When Robin would call me at 10 at night, at 2 in the morning, at 4 in the morning, saying, ‘Is it usable? Is any of this usable? Do I suck? What’s going on?’ I would reassure him. And so I said, ‘You are still you. I know it. The world knows it. You just need to remember that.’”

TV producer and writer David E. Kelley, who created Williams’ 2013-2014 series “The Crazy Ones,” offered similar insight, saying, “It was something eroding within him.”

“My faith in him never left, but I saw his morale crumbling,” Levy added of Williams. “I saw a guy who wasn’t himself and he thought that was unforgivable.”

The documentary was a collaboration between filmmaker Tylor Norwood and Susan Schneider Williams, the comedic actor’s widow. Williams tragically committed suicide back in 2014, much to the shock and horror of millions of fans.

This comes one week after Williams’ 31 year-old daughter Zelda announced that she was taking a break from social media on the anniversary of his death to avoid processing messages of support.

“As always, I will not be here,” she wrote. “It’s hard for me on regular, good days to remain the person expected to graciously accept the world’s need to share their memories of him and express their condolences for his loss.” She added that while she is “touched” by the “boundless continued love” for her dad, she sometimes feels “emotionally buried under a pile of other’s memories instead of my own.”

“After all, even roses by the truckload weigh a ton,” she added.