Judd Apatow Says Garry Shandling Achieved Zen Ahead of New HBO Documentary

Judd Apatow says his late mentor Garry Shandling became a nicer, wiser guy toward the end of his life, which will be explored in a new documentary about the comedian.

We spoke to Judd on "TMZ Live," and he gave us a rundown on what's behind his new project with HBO -- a 2-part documentary about his deceased pal and comedy great, Garry, that's airing March 26 and 27 on HBO at 8 PM.

Judd tells us Garry's diaries and journals -- which are the centerpieces in the doc -- revealed the comic became much more compassionate and giving throughout the years ... as neurotic of a creative genius as he was. He says Garry realized giving more to others was a W.

It sounds like a crazy deep dive into the mind of Shandling, who was groundbreakingly innovative with his shows like "It's Garry Shandling's Show" and "The Larry Sanders Show."