Sydney Sweeney, Dakota Johnson Put on Smoke Show for 'Madame Web' Premiere

There's a new 'Spider-Man' movie out this week that's all about the ladies -- the premiere for which runs the risk of getting you stuck on our page ... 'cause they were oozing sex appeal.

Of course, we're talking about "Madame Web"-- which stars Dakota Johnson, Sydney Sweeney, Emma Roberts and other female actors who lead the charge in fighting bad guys on the big screen. In front of cameras, though ... they were also leaving a mark.

Sydney, specifically, looked gorgeous ... with a body-hugging dress that was web-themed, and which fit her like a glove. Yeah, she was kinda pouring out of this thing -- tastefully, that is.

Dakota herself also turned heads with her outfit -- she had on this mesh/see-through gown that made it seem like she was completely naked underneath ... even though, she really wasn't. On the contrary, she had on a skin-colored leotard beneath her main dress.

Still, she was definitely allowing people's imagination to run wild ... and on both counts -- between Sydney and Dakota -- they certainly made a splash for their superhero flick.

Other cast members showed off their sweet duds as well ... Celeste O'Connor, Isabela Merced, Tahar Rahim, Adam Scott, Zosia Mamet and more. Everyone was dressed to the nines.

And, while everyone looked stunning ... it bears repeating, SS and DJ stole the show here.

Anyway, "Madame Web" hits theaters starting Wednesday -- but the box office projections for the movie are looking a little grim from the outset ... word is, it very well may flop.