1. Before it landed as a TV series on The CW executive-produced by Greg Berlanti, a studio executive initially envisioned Riverdale as a time-travel movie, according to creator Robert Aguirre-Sacasa.
"We go to the kickoff meeting and he said, 'You know, I've been thinking about this and I think you guys need to do something a little more high concept, a little bigger than a coming-of-age [story],'" Aguirre-Sacasa recounted at the 2017 Winter TCA Press Tour. "I said, 'Yeah, great. We're open to that.' He goes, 'I want you to think about time travel.' I say, 'What do you mean?' 'You know, Archie traveling through time.'"
The unnamed vice president then pitched comedian Louis C.K. to star as Archie Andrews.
2. A fan of the original Archie comics since childhood, Aguirre-Sacasa knew he needed to re-invent the upbeat series for modern audiences. Citing Twin Peaks, Our Town and The Breakfast Club as his inspirations, the writer told EW, "When we added the murder-mystery element to season one, the show unlocked creatively for me."
3. After a six-month search, K.J. Apa, then 18, was cast in the lead role of Archie, despite not having the right hair color.
"I think we literally saw every redheaded young guy in L.A. It certainly felt that way," Aguirre-Sacasa told Vulture of the casting process. "Every time that a redheaded guy came in, my heart swelled a little thinking, Let this be the redheaded boy who is the answer to all our prayers."
4. Apa's casting came down to the wire, with the pilot's production in jeopardy as producers scrambled to find their Archie. "We found K.J. three days before we were supposed to test Archies in front of the studio," Aguirre-Sacasa revealed. "So he was really slotted in at the last minute."
5. But the ultimate test was making sure the brunette New Zealand actor could pull off red hair, with the showrunner saying, "It's the dreaded day, because we have to dye this guy's hair and pray to God that that works, because, you know, some people's dye jobs look weird."
Fortunately, the bright hue suited Apa, though he does have to dye his hair every two weeks.
6. Apa isn't the only actor who had to change his hair color for the show, with Lili Reinhart going blonde to play Betty and Cole Sprouse dyed his naturally blonde locks black to portray Jughead Jones.
7. The Suite Life of Zack and Cody star, who took a five-year break from acting to attend NYU after his Disney days, was originally called in by producers to read for Archie, but Sprouse asked to audition for Jughead instead after he connected more with the outsider character and narrator.
8. While it is hard to imagine Madelaine Petsch as anyone but Cheryl Blossom, the actress revealed in a YouTube Q&A that she first read for Betty even though she was "pretty sure [the producers] always knew they wanted" her for the queen bee cheerleader.
9. Petsch met her ex-boyfriend Travis Mills after the musician also auditioned for the series.
"He messaged me on Facebook in January of season one and congratulated me on the show," she told Cosmopolitan in 2017. "He had auditioned for Jughead. I think we just randomly had mutual friends, so we added each other."
10. Before landing her breakout role in Netflix's 13 Reasons Why, Katherine Langford tested for Betty, with Camila Mendes, who landed the part of Veronica, telling EW, "I remember we went out and we got falafel with a guy who was auditioning for Archie."
11. It wouldn't be the show's only casting loss to 13 Reasons Why as Ross Butler left the show at the end of season one to become a full-time cast member on the Selena Gomez-produced drama. Charles Melton took over the role of Reggie.
12. Years before starring together on Riverdale, Mendes and Sprouse attended NYU at the same time, though he didn't remember they were classmates.
"Cole always laughs when I tell him that because I remember meeting him on certain occasions and he doesn't," Mendes told Office magazine in 2017. "I'm always like, 'Fine! Whatever! Sorry I'm not a child star!'"
She went on to jokingly call him "a weirdo" during their college years, explaining, "He had really long hair down to his butt cheeks. He was really shy too. I would see him at parties sometimes and I always kind of randomly talked to his brother [Dylan] but I never got a chance to talk to him because he was more to himself."
13. While filming the season one finale. Apa broke his hand during an intense scene in which Archie is attempting to save someone drowning in a frozen lake.
"I wasn't really punching the ice, but I got a bit too excited," he later admitted to TV Line. "I was punching a foam mat… [that was] sitting on the ice… it was cold, so I didn't really feel it. It wasn't until 20 minutes after that I realized I broke my hand. I didn't tell anyone."
14. Several Riverdale stars have dated during the show's run, including Sprouse and Reinhart, who were together for three years before they "permanently split" in early 2020, according to a rare statement from Sprouse.
Mendes and Melton also dated on-and-off for two years, with the co-stars sparking reconciliation rumors last summer when they were spotted at dinner.
15. Before Kiernan Shipka was cast as Sabrina Spellman in the Netflix spinoff series The Chilling Adventures of Sabrina, Aguire-Sacasa initially envisioned the Mad Men star as Betty.
The creator of both series also revealed to The Hollywood Reporter that he wrote the role of Ambrose in CAOS with Chance Perdomo in mind after he "was so taken by the actor's audition" for Jughead.