John Mulaney, left as George St. Geegland and Nick Kroll as Gil Faizon in “Oh, Hello” (Joan Marcus)so

NEW YORK — The ghastly wordsmith George St. Geegland and the bottom-drawer actor Gil Faizon have made it to Broadway. And would you believe? It’s right where they belong.

Their unlikely showbiz ascension is exactly the outcome we deserve, too — those of us who don’t mind a few lung-punishing laughing jags of an evening, in the theater. Or as George and Gil might pretentiously aver: a night on the Rialto. With an accent placed incorrectly on the “o.”

They are, separately and together, in their baggy corduroy pants and supercilious cluelessness, a hilarious act, the thirty-something comedians who portray the septuagenarian Upper West Side stooges of “Oh, Hello on Broadway.” Blessed with a gift for antic, topical wit, a palpable love of the stage and a bizarre fixation on tuna fish sandwiches, comedians John Mulaney and Nick Kroll hold a theater crowd in their loony spell for a giddy, galloping 90 minutes in the Lyceum Theatre, where the show had its official opening Monday night.

Judging from the audience’s enthusiastic greeting, the duo has acquired a following as a result of George and Gil’s appearances on Kroll’s now-ended Comedy Central sketch-comedy program, “Kroll Show”; a well-received off-Broadway run in 2015, and a national tour. It’s devotion well-earned, because these comedians, who met as undergraduates at Georgetown University, have sharpened to a very funny point an acumen for keeping an audience off-balance — and eager for more.

Their brand of comedy is a winning melange of all the brows: low, middle and high. One minute they’re making a potty joke and the next they are perpetrating a sight gag at the expense of “The Pillowman.” (You’re not familiar with that mid-2000s play by Martin McDonagh about fairy tales and torture in a totalitarian state? That’s okay: the bit will strike you as funny, anyway.) In a curtain speech at the start of the performance, nicely shepherded by a simpatico director, Alex Timbers, the team explains why they aimed for Broadway. “Theater is the hot new thing,” George says. “There’s ‘Hamilton’ … [long pause] … and no other example.”

George and Gil are Manhattan’s saddest-sack odd couple, virtually unemployable and seemingly unfit for any normal relationship: George boasts of the elegant symmetry of the deaths of his three wives, all of whom fell down the same flight of stairs. The big break that got away from Gil years earlier entailed an audition to be the voice of CBS, a tryout in which he thought the appropriate signoff would be, “This is CBS, baby!” So now, George, in his finite wisdom, has written a play for them both that allows Mulaney and Kroll to make fun of all sorts of theatrical conventions, like the slow fade into darkness at the end of a searing drama, or the stage-y, one-sided telephone conversations in which an actor holds a receiver and has to characterize for the audience all of the important words of the caller.

These are terrific bits of observational comedy — and more successful, I think, than an interlude halfway through, involving a third player who’s invited into the proceedings. I won’t spill any details, but it’s a gimmick with a marginal payoff. At least in comparison to the unalloyed fun we all have during the other 70 or so minutes with George and Gil and their assorted, hysterical hangups.

Oh, Hello on Broadway, by Nick Kroll and John Mulaney. Directed by Alex Timbers. Set, Scott Pask; costumes, Emily Rebholz; lighting, Jake Degroot; sound, M.L. Dogg; special effects, Basil Twist; makeup, Annamarie Tendler Mulaney. About 90 minutes. Tickets, $59-$250. At Lyceum Theatre, 149 W. 45th St., New York. Visit telecharge.com or call 212-239-6200.