There may be an alternate reality where “Big Bang Theory” and “Flight Attendant” veteran Kaley Cuoco could pull off the umpteenth professional assassin one and all agree is “the best” in an action comedy.

But it certainly won’t be one written by the screenwriter of the AI Kate Mara thriller nobody saw, “Morgan” and the director of TV’s “Reacher.”

Whatever you think about the perfunctory action beats — lame car chase, punchup at a subway stop, shootout in a Bavarian pine forest — “charmless” doesn’t really do justice to the corpse “Role Play” turns out to be.

Cuoco is Emma, another assassin-for-hire married to an unsuspecting spouse (David Oyelowo), with two unsuspecting kids. She takes her assignments from the mostly-unseen “Raj” (Rudi Dharmalingam), tells the fam she’s off to “Nebraska” or “St. Louis” for consulting work for “the regional office” or “the home office.”

And nobody asks, no one is the wiser.

But she’s mainly working these days, Raj insists, to pay the bills that keep this killer on “the dark net’s most-wanted list” hidden from Sovereign, an entity that wants her, or wants her dead.

But forgetting their wedding anniversary puts her in a bind. That’s how the murderous professional role player winds up in a swank NYC hotel bar in a little black dress, pretending to be in “finance,” waiting on her eager-to-role-play husband under a different name, but waylaid by a dapper, insistent and pushy older gent (Bill Nighy) who has plainly “made” her.

The deadly game’s afoot, with cops visiting her husband and an old foe (Connie Nielsen) filling the unsuspecting boob on who his wife really is.

The scenes with Nighy have something like a spark about them, banter as professional parry and thrust between vodka martinis and something one could never imagine Bill Nighy ordering in any guise, including that of rival killer “Bob” — “shots.”

“You see that Panamanian diplomant they pulled out of the East River last night?”

Maybe. Maybe not.

“You know the drill, Bob.”

That’s the burden “Role Play” never sheds. We know the drill. Every move, every twist, every quest, every moment of filler pointing us to a finale we see coming an hour off.

Cuoco only plays to her strengths in the Nighy scenes. Oyelowo can handle comedy, as he basically steals “The Book of Clarence.” But he has nothing funny or interesting to play, here.

Nielsen? Whatever. That goes for every cardboard character and every stale twist leading up to her appearance.

Rating: R, graphic violence, sexual situations, alcohol, profanity

Cast: Kaley Cuoco, David Oyelowo, Bill Nighy, Rudi Dharmalingam and Connie Nielsen.

Credits: Directed by Thomas Vincent, scripted by An MGM/Amazon Prime release.

Running time: 1:41