Kevin Spacey's getting back into the public eye after his acquittal in London last summer ... and a lot of people are none too happy about it -- which they're making quite clear.

Here's the deal ... the controversial actor's scheduled to appear at Mad Monster Party 2024 in North Carolina next month -- a three-day convention dedicated to all things horror/pop culture. Other stars like Kiefer Sutherland, Lou Diamond Phillips, Taryn Manning, Jason Patric and more are attending the event as well.

Clearly, organizers are jazzed at KS' inclusion ... touting his accolades and selling pro photo-ops for big money -- no selfies allowed at the autograph table. If you want a pic, you'll have to shell out $225.

The photo opportunities are themed too ... Friday, Feb 16 they'll set one up for "The Usual Suspects"-type pic, Saturday's for "Se7en" and Sunday, Feb. 18 will see Kevin take "House of Cards" pics -- basically, Spacey's greatest hits.

Now, it didn't take long for people to voice their outrage ... with a good handful of folks saying in unequivocal terms they find the organizers reprehensible for giving Spacey a platform after all of the allegations leveled against him. Just check their comments.

In essence, a lot of fans don't seem to care Kevin was acquitted last year on a host of charges -- as we previously reported, Spacey was found not guilty of nine total counts based on a host of sexual assault allegations in a London court last year after a lengthy trial.

He's also been sued in New York for a different alleged sexual assault ... a massage therapist is claiming the 64-year-old made unwanted and inappropriate sexual advances toward him during three 90-minute sessions back in 2016.

The two-time Academy Award winner's never been convicted of a crime for any of the allegations brought against him ... and he's denied any and all wrongdoing, FWIW.

It'll be interesting to see how many fans want to take a pic with Spacey next month ... or if any protests will spring up in NC.