"Riverdale" season three finale
photo: CW

Riverdale fans were left with a major cliffhanger at the end of season three and have been chomping at the bit for any snippets of information about the upcoming fourth season ever since. 

Lili Reinhart, Camila Mendes, KJ Apa, Cole Sprouse, and the rest of the Riverdale cast have traveled back to Vancouver to begin filming. Without giving too much away, some of the stars of the series teased at what is to come with behind-the-scenes sneak peeks. Brace yourselves: There are some major tearjerker moments sure to come during the first episode, according to some of these posts.

Mädchen Amick (Alice Cooper) posted a group selfie dedicated to the late Luke Perry. 

Amick shared a shot from the group table read of the first episode's script, and it tugged at the cast's heartstrings. The first episode will be dedicated to Luke Perry and his character Fred Andrews. 

"There was nothing but love, memories and mourning for our beloved Luke as we honor him in our first episode back #wemissyouluke #inmemoriam#riverdale #S4 #tableread," Amick captioned the post that most of the cast shared. 

Marisol Nichols (Hermione Lodge) reposted Amick's Instagram and captioned it, "1st read thru of Season 4 #riverdale. Dedicated to Luke. We love you, man. Honoring you the best way we know how." 

Vanessa Morgan (Toni Topaz) shared a lighthearted snap in bed with Madelaine Petsch (Cheryl Blossom).

The fan-favorite couple (that shippers have nicknamed Choni) lounge in bed during the first episode, which is a common theme among the show's leads for the first day on set. 

"First day of Season 4 & we get to lay in bed all scene hayyyy," Morgan captioned her Instagram post. Morgan also shared a shot of her character's notorious long purple-pink wig to her Instagram Story and a shot with costar Skeet Ulrich (FP Jones). 

Ulrich smoldered on his Instagram Story in FP's sheriff uniform. 

Ulrich is back on set and ready for business as FP Jones the cop. One of the latest Riverdale twists was the return of Jones' and Alice Cooper's long lost son, Charles Smith. Charles (Wyatt Nash) revealed himself to Betty (Lili Reinhart) and Jughead (Cole Sprouse) as their shared half-brother at the end of the season three finale, plus he is an FBI agent on the case to disband the Farm and retrieve his and Betty's mother.  

Petsch also shared a shot of a script and the graphic for the fourth season, which replaces the "A" in Riverdale with a "4." 

Petsch shared the cover of the top-secret script as the crew returned to Vancouver to shoot the fourth season. Upon closer inspection of the script's cover, it's difficult to say if any spoilers can be determined, but there is a faint "Happy Birthday" card peeking out of a box of "stuff" on the comic strip graphic. The Cheryl Blossom actor also posed with her on-screen girlfriend, Morgan, and a cute dog outside a trailer. She captioned the post, "Back to your regularly scheduled programming." 

Lili Reinhart (Betty Cooper) shared a shot of her character's bedroom — er, Jughead's?

Once again, one of the leading ladies is filming in her character's room. "Here we go," Reinhart wrote over her shot of the set. In the finale, the core four pledged to have a drama-free senior year, but of course that was quickly shut down with an ominous flash-forward.

Casey Cott (Kevin Keller) and Charles Melton (Reggie Mantle) have returned and are already messing around on set. 

"She’s back #season4 #riverdale," Cott captioned this shot of Melton riding a bike. Some fans quickly jumped to conclusions and started theorizing about the shot. 

"What's up with all of you posting about Charles? KJ, Cole and now you," one person wrote. 

Another commented, "Is this a spoiler?" 

It's true, all three boys posted a shot of Melton on their way to Vancouver in one way or another, but that's most likely a testament to their off-screen friendship than anything to do with the upcoming season. 

Camila Mendes (Veronica Lodge) also revealed that her character also spends a lot of time in bed during the first episode. 

Is this a sleepover episode, or is Veronica in some kind of trouble? Mendes tweeted of her first day back on set, "first day of filming season 4 and all i gotta do is lie in bed and pretend to be asleep." Some fans warned her of spoilers, while others envied her high-paying gig that required her to "sleep" all day. 

Cole Sprouse (Jughead Jones) posted a bizarre booty-slapping video to his Instagram with Charles Melton, but most fans are just grateful that that means he's in season four in some way. 

At the end of season three, Jughead's fate was left unknown. However, Sprouse has been spotted in multiple set photos, so he definitely makes an appearance, but it's still unclear whether or not his character makes it out unscathed. 

The Jughead star captioned this bizarre slow motion video, "@melton and I going method for season 4." If season four is anything like this video, then I am here for it.