Louis C.K. Plugs New Special During 'SNL' Broadcast with Ad Buy

Louis C.K. comedy comeback is in full swing -- and his latest stop is over at "Saturday Night Live" ... which gave him a nice time slot for a new ad plugging his stand-up special.

The controversial comedian appeared across TV screens all over the NY area Saturday while 'SNL' was airing, with a local promo showcasing his latest offering, 'Sorry,' which he just released on his own site. The ad ran at about the 10-minute mark into the broadcast.

The spot runs for 30 seconds, and it features the song "Louie Louie" by The Kingsmen playing in the background ... as clips of LCK dishing his latest joke play throughout.

Unclear where he filmed this, or when -- but it's no secret the guy's been touring all over the country these past several months ... and word is, his live shows have been packed to the gills and selling out like crazy -- even in places like L.A. and NYC.

Like we said, this special isn't airing or being sold anywhere besides his own online presence -- so folks definitely have to go out of their way to buy and watch it -- but still ... people are pretty pissed that he's attempting to resurface at all, let alone with an assist from NBC.

Of course, 'SNL' probably has no say over the placement of the ad -- there's a whole other department handling that -- but the idea NBC was cool with taking Louis' money at all is what seems to be irking the Twitter crowd. And yes, "cancel culture" is again being dissected.