'Riverdale' Stars Lili Reinhart and Camila Mendes Are Planning Their Couple's Costume -- With Each Other!

Betty Veronica Riverdale
The CW

These two 'Riverdale' co-stars and IRL besties are planning the ultimate couple's costume... with each other!

Who says couple's costumes have to be reserved for your significant other?

Riverdale's Lili Reinhart and Camila Mendes are total friendship goals -- the two appear to be planning an epic couple's costume together for Halloween. Reinhart, 22, broke the news on Twitter Thursday, much to the delight of Riverdale fans everywhere -- a message that Mendes, 24, instantly retweeted.

"Don’t want to get anyone overly excited," she wrote. "But @CamilaMendes and I have a very special Halloween couples costume this year."

Fans immediately started speculating what the IRL besties' Halloween getups would be, suggesting everything from Betty and Veronica (Riverdale shoutout) to the Powerpuff Girls to Lizzie and Isabella from The Lizzie McGuire Movie.

The ironic part is that Reinhart and Mendes each already have significant others in the form of their co-stars, Cole Sprouse and Charles Melton, respectively. Rumors of a romance between Reinhart and Sprouse, 26, sparked when the two were spotted sharing a sweet smooch earlier this year in Paris, and the duo made their public debut as a couple a few weeks later at the Met Gala

More recently, Mendes and Melton, 27, made their relationship Instagram official earlier this month by sharing a sweet PDA photo. Reinhart responded to her BFF's post by commenting with a simple and sweet tulip emoji. ET confirmed that the two are indeed dating.

Riverdale airs Wednesdays at 8 p.m. ET/PT on The CW. For more on the series' off-screen relationships, watch the clip below.