For their first Broadway Christmas show, American Idol rivals Ruben Studdard and Clay Aiken are dreaming of holiday TV variety specials of yore from the likes of Andy Williams, Sonny and Cher and Dean Martin. Holiday lesson: Careful what you wish for.

If you’ve watched any of those old specials on retro channels like Get TV this season, you’ll know a small dollop of Christmas kitsch covers a lot of cookie. Ruben and Clay are spreading it wide and thin at the Imperial Theatre.

Loaded with Christmas songs both religious and secular (the duo sing together, solo and with a quintet of fresh-faced and strong-voiced backers), Ruben & Clay’s First Annual Christmas Carol Family Fun Pageant Spectacular Reunion Show, opening tonight, pads the proceedings with intentionally cheesy sketch comedy, corny banter and, more successfully, thoughtful personal nostalgia.

Since the show seems to come from a place of good cheer – and some proceeds will go to charity – let’s get the Grinching out of the way: Neither Aiken nor Studdard have anywhere close to the comedic chops needed to pull off something like this. Their timing is imprecise, to put it mildly, with Studdard the more egregiously off beat.

The odd couple schtick is forced and undercooked. Aiken insists on repeatedly using the show’s full title, annoying Studdard no end. Aiken demands that Studdard drop a dollar into a red stocking whenever the latter curses or says something un-family friendly. Swiping that great, probably apocryphal Tallulah Bankhead-Loretta Young anecdote, Studdard “pre-pays” $10. No, he doesn’t follow up with Bankhead’s f’ing great punchline.

Fortunately, Ruben & Clay (or Clay & Ruben – the ever-changing billing is a running gag) doesn’t take its joking seriously (nor does the design, with a campy holiday hearth backdrop and ugly Christmas sweater costumes). For one bit, the show takes inspiration from the old Laugh-In staple of heads popping through a “joke wall” to tell intentionally creaky jokes – Frosty having a meltdown and Snowmen having snow balls. The stars frequently attempt to out-do one another in over-the-top caroling, and Clay does an audience participation bit with holiday-themed Mad Libs that might play better on some evenings than the one I saw.

Musically, Ruben & Clay is on surer footing, with Studdard’s silky R&B and gospel takes on the holiday tunes mixing very well with Aiken’s more Broadway-belting style, and despite what their old judges might call some pitchiness here and there, the two make for fine carolers (as do their perky back-up revelers:  Farah Alvin, Ken Arpino, Julian Diaz-Granados, La’Nette Wallace, and Khaila Wilcoxon).

Written by Ken Arpino and Jesse Joyce, directed by Jonathan Tessero, with musical direction by Ben Cohn and musical staging by Lisa Shriver, the show turns heartfelt after intermission, with a video extolling Aiken’s National Inclusion Project for autistic children, and the stars’ reminiscences of Christmases Past (particularly moving are Studdard’s memories of his late brother).

The singing returns full force soon enough – Ruben & Clay is at its most enjoyable when the songs are flowing (and note to Fox News chicken littles: No war on Christmas here – neither the tune roster nor the Christmas memories retreat from the overtly religious).

With an affordable entry point – tickets start at $39 – Ruben & Clay is family friendly in more ways than one. The production bills itself as the “first annual,” and if next year is in the cards the duo might consider a less is more strategy: Ditch the intermission, trim the hokum and carol to your hearts’ content. Ninety minutes tops.

Ruben & Clay’s First Annual Christmas Carol Family Fun Pageant Spectacular Reunion Show is produced by Jeffrey Chrzczon, Side Effects Include, and Josh Pultz/Amplified Entertainment.