AceShowbiz -

"The Big Bang Theory" releases a still from the upcoming April 12 episode which unmistakably will tickle out laughter as well as curiosity. The four nerds are in the comic book store, dressed in superheroes costume and crossing the gender.

Wolowitz is Batgirl, Sheldon is Wonder Woman, Leonard is Supergirl while Raj, who is the only one excited about the costume, is Catwoman. "I will say this. This is not the worst thing that happens to someone in this episode," executive producer Bill Prady told Entertainment Weekly.

In the episode, a fight between Leonard and Penny threatens their relationship. EW's Ausiello previously questioned Prady whether the couple will head to splitsville. The producer reminded that fans "shouldn't look at what happens in a single episode as definitive. The relationships between these characters - especially romantic relationships - are messy."

Also in the episode, Wil Wheaton will come back as himself and battles Sheldon in bowling.