It is going to be a happy Christmas for the West family with the arrival of a new member in the upcoming episode of The CW series "The Flash."

In "Running to Stand Still," Comicbook reports that the famous comic book speedster Wally West (Keiynan Lonsdale) will arrive in Central City. His father Joe (Jesse L. Martin) does not know about his existence yet, but his sister Iris (Candice Patton) does. She will reportedly be the one to introduce Wally to Joe. How will the West patriarch react to this revelation? With Wally's visit during the holidays, the family will celebrate Yuletide together. Will it be a merry one?

Speaking to KSite TV, Patton revealed that the cast knew beforehand about the character's arrival. But at that time, she did not know yet how Iris and Wally would interact as siblings. She said the two would share "some sort of dialogue," but beyond that, the producers were keeping them in the dark. As for the Christmas episode, she shared that it would be full of drama, especially for the West family.

"We definitely know Wally's going to make an appearance. I know that's a huge point of excitement for a lot of fans... It's a lot about family. It's a good Christmas episode. Just like the last one. Good villain, and good love, and good heart," the actress said.

Meanwhile, executive producer Andrew Kreisberg told Entertainment Weekly back in September that Wally would not be a full-pledged speedster when he heads to the city. In the comics, he is the first Kid Flash. Kreisberg revealed that Wally would be just an ordinary teenager when the viewers first see him in the show. He also added that the character would be introduced in the same way Roy Harper/Arsenal (Colton Haynes) was introduced on "Arrow."

"The Flash" episode 9 did not air on Nov. 24. Instead, it will be shown on Dec. 8 at 8 p.m. EST on The CW.