Billy Bush has plenty of advice for Will Smith on how to deal with a moment that could badly stain his career in Hollywood … and he’s reached out to Will offering help.

We got Billy Wednesday at Judi’s Deli in Beverly Hills … and he scoffed at people who are calling for Will’s cancellation, calling it “crazy” and “ridiculous.”

Billy, who’s been through it himself, says one bad moment doesn’t define a person’s life, even something as huge as Will slapping Chris Rock at The Oscars.

Billy isn’t defending Will’s conduct, but he says everyone snaps from time to time, and he does acknowledge Will’s meltdown was epic … nevertheless, B.B. thinks Will’s already paid a steep price, asking, “You don’t think that guy’s hurting enough?”

Billy says he contacted Will’s publicist and urged the actor to read a book called “The Daily Stoic,” a book he says has critical life lessons that will help Will navigate troubled waters.

Of course, Billy was fired from “Today” after the infamous “Access Hollywood” bus audio surfaced shortly before the 2016 election, in which Billy laughs at Donald Trump‘s hyper-offensive comments about women. So now Billy wants to offer the lessons he learned about overcoming obstacles.