Colin Jost was strong-armed into making his wife, Scarlett Johansson, the butt of a joke he was forced to deliver on 'SNL' ... and he has his good pal Michael Che to thank for it.

Last night was the sketch comedy series' last show of the year, and every Christmas -- the two "Weekend Update" hosts have a tradition of writing jokes for one another that the other hasn't seen ... but has to read in front of the audience as if it's coming straight from them.

It's one of the better segments on the show these days, and 2023's iteration didn't disappoint -- especially for one crack Che made Colin read ... at the expense of his A-lister spouse.

The premise was highlighting a new NY law that now allows movie theaters to serve booze -- which Colin then said would serve as the only way he can get through ScarJo's "little art movies" ... with a flash to an OTS graphic of her in "Black Widow."

It was a pretty sick burn (from Che) and the audience definitely seemed to notice ... cackling and dropping the collective "OOOOOHHHHHHH" to signify how wild it was that her hubby was saying that.

Of course, it's all in good fun ... and Colin rolled with it, including reading the tail end of Che's edgy joke for him -- in which he said, "I'm kidding, honey. I love all of your movies. And if you ask me, you're an even better Black widow than Coretta Scott King."

The funniest part about all of Colin's jokes -- which were written to be pretty racist against Black people -- is that Che brought out a (fake) civil rights activist to sit next to him while he delivered all of these ... and Che ribbed him about it each and every time.

Definitely got big laughs ... and certainly worth the year-long wait. 'SNL' is back in January.