Now, he's on set for season 2, and clearly loving it.
Posting to Twitter, he revealed, "My first day on set with the cast was like opening a Christmas gift you didn't think your parents could afford in a million years."
Well that metaphor got us in the damn #feels.
Charles has made appearances in shows like American Horror Story and Glee, but none as large as his character Reggie, who has been guaranteed a bigger story line for season 2.
Show runner, Roberto Aguirre-Sacasa even shared a photo of Charles with Ashleigh Murray who played Josie.
"A BIG #Pussycat welcome 2 @_MELTON_ as #Riverdale's sexy new Reggie Mantle! I can already tease... these 2 are TROUBLE," he wrote on Twitter.
UMM, INTO THIS!!!!!
Ashleigh has already told E! News that Josie and Reggie will date in season 2.
This is definitely a #ship we can get behind. It's not the first time Roberto has teased the two as a couple either, posting this artwork on his Twitter last week:
#Bughead may be cute but we think #Rosie will be season 2's official 'it' couple.