Stop.

Someone in a position of power should have said just that long before “Collateral Beauty” ever made it to the big screen, and well before (behold this cast!) Will Smith, Helen Mirren, Edward Norton, Kate Winslet, Keira Knightley and Michael Pena climbed aboard this fundamentally flawed vehicle, convinced they had a heartwarming, spiritually uplifting tale to tell.

“Collateral Beauty” is a fraud. It is built on a foundation so contrived, so off-putting, so treacly, the most miraculous thing about this movie is this movie was actually made.

I’m going to discuss a few key early plot points (without spoiling any of the major developments), in the hope you’ll understand why I was so flabbergasted and flummoxed by this cheesy attempt at a holiday tear-jerker.

Will Smith is one of my favorite big-time movie stars of the last 20 years, but he takes a big swing and a miss here playing Howard, a legendary advertising genius heading a hipster Soho agency.

“We’re not just selling s—,” Howard says in an address to his fawning troops — but that’s exactly what they’re doing, and that’s exactly what this movie is doing.

Flash forward three years. Howard looks as if he’s aged a decade. He’s detached and disinterested. The agency is losing business left and right, but Howard doesn’t care.

That’s because Howard is broken. His 6-year-old daughter was taken from him by a rare form of cancer two years ago — and ever since then, Howard has shut out everyone, from his wife (now his ex-wife) to his business partners to his employees.

Edward Norton’s Whit, Kate Winslet’s Claire and Michael Pena’s Simon are Howard’s business partners and closest friends. They love Howard and they’ve supported him and covered for him — but they can’t stand by any longer and watch Howard destroy the agency and everything they’ve all worked so hard to attain.

Problem is, Howard has 60 percent ownership of the company. How do they wrestle control from him?

Turns out Whit had an affair with a junior account executive at the agency. It destroyed Whit’s marriage, and now Whit’s daughter won’t even talk to him.

What does that have to do with the whole overthrow-Howard mission? Glad you asked! A private investigator named Sally Price (Ann Dowd) uncovered the aforementioned affair. So Whit, Claire and Simon hire that same investigator to tail Howard and dig up some dirt on him so they can prove he’s not competent to run the company. I’m serious.

Sally learns Howard has been sending letters — not to people, but to “Love,” “Death” and “Time.”

And this is where “Collateral” goes utterly mad.

Howard’s friends hatch a plan: They’ll hire actors to portray Love, Death and Time, respectively. The actors will confront Howard about the letters he’s written. Howard will actually believe he’s talking to Love and Death and Time, Sally the private investigator will record those moments — and voila! There’s your proof Howard is crazy.

Wow. Howard’s friends really suck.

Helen Mirren is Brigitte, who will portray Death. Keira Knightley is Amy, who will play Love. Jacob Lattimore is Raffi, cast in the role of Time. One by one, in character, they infiltrate Howard’s life, recite the contents of his letters back to him and give him grief about him wallowing in his grief.

Meanwhile, each of Howard’s so-called friends is dealing with a crisis with obvious symbolic ties to Howard’s tragic past — and each is paired up with the actor playing just the right “character” to further hammer home the point.

Of course, Whit and Clair and Simon are slow to realize that, because they’re too busy being the worst friends in the world with their elaborate and ludicrous plan to prove Howard is insane.

The screenplay for “Collateral Beauty” tips off the two biggest “surprises” with all the subtlety of a lout in the theater who has already seen the movie and shouts, “Didja see what just happened there! You know what that means, right?”

Production values are just as phony as the story. “Collateral Beauty” is set mostly during the holidays in New York — but one minute there’s a neighborhood scene in which every single house looks like it was decorated by a Hollywood crew, and the next minute there’s a scene with not a Christmas decoration in sight.

It’s quite possible “Collateral Beauty” will move you to tears. Then again, it’s quite possible you’ve been moved to tears by commercials about dogs that befriend horses, viral videos where students surprise a retiring teacher with a musical tribute and/or violently yanking out one of your own nose hairs.

All three of those examples go about earning your emotions in a more legitimate way than this nonsense.

New Line Cinema presents a film directed by David Frankel and written by Allan Loeb. Rated PG-13 (for thematic elements and brief strong language). Running time: 93 minutes. Opens Friday at local theaters.