'Riverdale': Jughead's Mom and Sister Arrive in "Outbreak" Synopsis

The CW has released the official synopsis for "Chapter Forty-Three: Outbreak," the December 12 episode of Riverdale.

The episode will feature the first appearances of Jughead's mom Gladys (Gina Gershon) and his little sister Jellybean (Trinity Likins) -- but some fans may be disappointed to learn that they aren't coming to Riverdale. Instead, their appearance is part of a road trip storyline featuring Archie and Jughead.

"It's nice to have a little more background on Jughead's character and his family life and a lore that has sort of been hinted at since season one really, and kind of loose ends that — that without saying too much — do get addressed and do get talked about," series star Cole Sprouse said during a recent visit to the set.

And, of course, Archie and Jughead have been best friends since they were kids, so it is not like Archie will not be happy to see Gladys and JB again, either.

"They have a relationship, but it was a long time ago, like when Archie was maybe seven or eight years old," Apa explained. "And even then, they probably didn't have that much face time, but he's definitely familiar with their family. But nowhere near as familiar with his sister, I don't think. I think Archie is almost as familiar with Jughead's mom as Jughead is, almost. There's some fun stuff coming out with that."

You can see the synopsis below.

GINA GERSHON GUEST STARS AS JUGHEAD'S MOTHER GLADYS JONES

On the road and running out of places to stay, Jughead (Cole Sprouse) and Archie (KJ Apa) head to Toledo to visit Jughead's mother Gladys (guest star Gina Gershon) and sister Jellybean (guest star Trinity Likins). Back in Riverdale, Betty (Lili Reinhart) inches closer to uncovering the truth about Griffins & Gargoyles, while Veronica (Camila Mendes) and Cheryl (Madelaine Petsch) take on Hiram (Mark Consuelos), Hermoine (Marisol Nichols) and Penelope (guest star Nathalie Boltt) after more students fall victim to seizures. Madchen Amick, Luke Perry, Skeet Ulrich, Casey Cott, Charles Melton and Vanessa Morgan also star. John Kretchmer directed the episode written by James DeWille.

Riverdale airs on Wednesday nights at 8 p.m. ET/PT on The CW. "Chapter Forty-Three: Outbreak" will premiere on December 12.