A since-deleted Reddit post showed that the ad does take up an entire screen and warns user to play the ad or continue.
Some users even found that they had a bug, The Verge reports, which prevented them from skipping the ad and having to watch the promotion.
"We are testing whether surfacing recommendations between episodes helps members discover stories they will enjoy faster," the service said in a statement to the Verge.
Netflix did assert, however, that the feature is not a permanent one.
But the damage had already been done, with many voicing their discontent and plans to cancel their subscriptions if they had to watch ads.
One user said: "Hey @netflix , we pay a subscription so we don't have to see ads for s**t. We. Don't. Want. This. You have a lot of market share right now. You do this, and you will quickly learn that we users don't have brand loyalty when a competitor without commercials pops up."
Another added: "Netflix has started putting ads for its s****y standup specials in between episodes of frasier. and probably other shows but ive got frasier on and it feels particularly offensive. keep frasier pure."
"Hey @netflix I can tolerate the ads at the top of my list of shows but between every episode I watch is getting stupid," chimed in a user.
A different user asserted: "I hope it's not true that @netflix is introducing ads into its programming. I literally pay money to Netflix so that I don't have to see ads. I'd rather stop watching Netflix than have them run ads. Swear to god the first one I see I'm cancelling."