First Look: Penny Gets An Unexpected Visit From Her Ex On The Big Bang Theory

Sheldon makes a surprising suggestion.

Sheldon makes a surprising suggestion.

When the gang goes to wine tasting, Bernadette stays behind and gets stuck hanging out with Sheldon. Plus, everyone struggles to keep their cool when they run into Penny's ex-boyfriend, Zack, and are introduced to Raj's new lady-friend, Claire, on the next episode of The Big Bang Theory entitled "The Fermentation Bifurcation." 
Penny chuckles at Sheldon while the gang partakes in some takeout.

Penny chuckles at Sheldon while the gang partakes in some takeout.

"The Fermentation Bifurcation" (Episode 22, Season 9 of The Big Bang Theory)
Bernadette agrees to a solo hang session with Sheldon.

Bernadette agrees to a solo hang session with Sheldon.

"The Fermentation Bifurcation" (Episode 22, Season 9 of The Big Bang Theory)
Sheldon plans an exciting evening while Leonard quietly reads on the couch.

Sheldon plans an exciting evening while Leonard quietly reads on the couch.

"The Fermentation Bifurcation" (Episode 22, Season 9 of The Big Bang Theory)
Leonard reads up on wine so he can participate in any potential fermentation conversations.

Leonard reads up on wine so he can participate in any potential fermentation conversations.

"The Fermentation Bifurcation" (Episode 22, Season 9 of The Big Bang Theory)
Amy and Howard have a good laugh at the wine bar.

Amy and Howard have a good laugh at the wine bar.

"The Fermentation Bifurcation" (Episode 22, Season 9 of The Big Bang Theory)
Raj prepares the gang to meet his new girlfriend, Claire.

Raj prepares the gang to meet his new girlfriend, Claire.

"The Fermentation Bifurcation" (Episode 22, Season 9 of The Big Bang Theory)
Penny talks to Raj about his new love interest.

Penny talks to Raj about his new love interest.

"The Fermentation Bifurcation" (Episode 22, Season 9 of The Big Bang Theory)
Sheldon opens a bottle of sparkling cider for Bernadette and himself.

Sheldon opens a bottle of sparkling cider for Bernadette and himself.

"The Fermentation Bifurcation" (Episode 22, Season 9 of The Big Bang Theory)
Leonard and Amy sniff their wine, trying to smell the aromas better.

Leonard and Amy sniff their wine, trying to smell the aromas better.

"The Fermentation Bifurcation" (Episode 22, Season 9 of The Big Bang Theory)
Penny runs into her ex-boyfriend Zack at the wine-tasting event.

Penny runs into her ex-boyfriend Zack at the wine-tasting event.

"The Fermentation Bifurcation" (Episode 22, Season 9 of The Big Bang Theory)
Zack makes things a bit awkward for Penny and the group.

Zack makes things a bit awkward for Penny and the group.

"The Fermentation Bifurcation" (Episode 22, Season 9 of The Big Bang Theory)
Sheldon shows off his trains to Bernadette.

Sheldon shows off his trains to Bernadette.

"The Fermentation Bifurcation" (Episode 22, Season 9 of The Big Bang Theory)
Leonard and Howard share a pensive moment at the bar.

Leonard and Howard share a pensive moment at the bar.

"The Fermentation Bifurcation" (Episode 22, Season 9 of The Big Bang Theory)
Raj introduces his new girlfriend, Claire, to his close friends.

Raj introduces his new girlfriend, Claire, to his close friends.

"The Fermentation Bifurcation" (Episode 22, Season 9 of The Big Bang Theory)
Bernadette and Sheldon play a game together.

Bernadette and Sheldon play a game together.

"The Fermentation Bifurcation" (Episode 22, Season 9 of The Big Bang Theory)
Penny's ex, Zack, lingers around Claire and Raj.

Penny's ex, Zack, lingers around Claire and Raj.

"The Fermentation Bifurcation" (Episode 22, Season 9 of The Big Bang Theory)

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