The first time I heard that Britishism disguised by the clever British acronym “Cee YoU Next Tuesday” was right around the first of October, 1980.

And because it came out of the plummy, posh Oscar-winning mouth of the late Glenda Jackson, it went right by me.

I can pinpoint this date because she said it in the movie “Hopscotch,” a jaunty little spy comedy starring her and set up as a star vehicle for Walter Matthau. Last night I spat out my Guinness in comic surprise at having missed the joke, the first time around.

Jackson wasn’t the first person I heard use the Yiddishism “feygeleh,” probably the origin of the gay slur, something her character drops into a description her character is passing onto Kendig, played by the Yiddish-mad Matthau. Mel Brooks slipped it into “Blazing Saddles” and maybe elsewhere, if memory serves. It too, is kind of an out-of-nowhere gag that trots by without notice.

The first time I interviewed Matthau was about the movie “I.Q.,” in which he played The tallest Einstein Ever. As he and the great scientist were contemporaneous enough to have possibly met, I asked him when he’d have said to Albert E. if he had the chance.

Matthau said “I’d have probably have told him a joke in Yiddish. Einstein LOVED Yiddish!”

Then Matthau, who got his start in New York’s Yiddish theater, launched into an off-color comic anecdote/joke about three men, in Yiddish. It took a minute of two to get to the punchline, in Yiddish. Which he then breathlessly translated. HILARIOUSLY.

Matthau was mad for Yiddish, relished a joke well-told, adored Mozart and loved the high life he both worked his way into with his acting, and that he married into by tying the knot with the famous playwright William Saroyan’s ex-wife, the celebrated socialite Carol Marcus.

“Hopscotch” was thus tailor-made for the then-60 year-old Matthau, a comic actor having a grand second wind in the late ’70s and early ’80s. He’d play a globe-trotting spy who doesn’t take being put out to pasture well.

Using his spycraft, and with a little help from a retired Brit lady spook and lover (Jackson), Kendig” would “Hopscotch” around Europe and America, teasing his amoral CIA boss (Ned Beatty) and his Old World Charm Soviet nemesis (Herbert Lom) with a tell-all “tell-the-truth” memoir about spy-shenanigans with dictators like Somoza and Papa Doc and the “mysterious death of Dag Hammarskjold.”

In a post-Watergate age of growing government mistrust and government agency misbehavior, the rival spy agencies would do anything to silence this rogue agent who was telling all their secrets. Kendig? He’d travel from Salzburg to Switzerland, London to Marseilles and even Savannah, skipping along, using old contacts and everything he knew about his hunters to evade them and vex them no end, sending them one scandalized chapter at a time.

“Hopscotch” thus becomes a comic thriller and travelogue, with Matthau in assorted Homberg hats, safari jackets and trenchcoats, merrily plotting this trick, that escape and the occasional humiliation, singing along, humming and on occasion conducting the music of Wolfgang Amadeus Mozart every step of the way.

British cinematographer/producer/director Ronald Neame, who got his start shooting the films of David Lean in the ’40s, wasn’t known for comedy. “The Poseidon Adventure” and “The Prime of Miss Jean Brody” were his most famous films. But Mozart turns this bon bon of a movie into a bouncy little gambol of a Grand Tour.

How much did Matthau love Mozart? On his one visit to “Saturday Night Live,” he threw his weight around (a lot, according to the cast) and made cast-member Garrett Morris the night’s musical guest, singing a Mozart aria.

The film is a case study in effortlessness. It’s never hilarious, but the laughs stick with you and there are chuckles scattered throughout this picture. Matthau is playing at playing a spy, and he makes damned sure you know he isn’t trying too hard.

In one scene, recognized as a blown take that got in the movie, he’s typing away at his book in the vacation home of his hateful, violent (and foul-mouthed) boss, “C U Next Tuesday Meyerson (Beatty)” outside of Savannah when Kendig returns his typewriter carriage a bit clumsily and knocks over his just-opened bottle of Michelob.

Not in the script. Matthau, unrattled, stays in character, picks up the beer the way every one of us would in such a mishap and drinks it to stop it from foaming all over everything.

The whole movie is like that, with Jackson lending her equally effortless “touch of class” to the proceedings right from her “meet cute” introduction.

“Oh where have you BEEEEEN you old GOAT?”

I hadn’t watched “Hopscotch” all the way through in decades, but the scenes that stick still stick, and the charm just twinkles off scene after scene. Matthau and Jackson, who had clicked in “House Calls” a couple of years earlier, have a laid-back chemistry that’s hard to top. Beatty makes a perfectly vile autocratic villain. Lom, the “Pink Panther” series veteran, stands out among the supporting cast, and look for Matthau’s son and stepdaughter in cute bit parts.

Munich, Salzburg and Savannah and environs make it feel Bond-lite, a well-traveled caper comedy as spy thriller with laughs instead of bloodshed and stakes so low you never for a moment fear for the safety of our “Barber of Seville” singing hero.

It’s as watchable as ever, so See it Next Tuesday or at your convenience.

Rating: R, profanity

Cast: Walter Matthau, Glenda Jackson, Ned Beatty, Herbert Lom and Sam Waterston.

Credits: Directed by Ronald Neame, scripted by Brian Garfield and Bryan Forbes, based on the novel by Brian Garfield. An AVCO Embassy release on Movies!, Amazon, Youtube, etc.

Running time: 1:46