Sheldon and Penny
Sheldon and PennyTwitter/The Big Bang Theory

Season 8 of "The Big Bang Theory" is coming to a close on Thursday with the episode "The Commitment Determination," and it will see the main leads taking life-changing decisions. The episode can be viewed online on CBS.

The season finale is expected to shock fans, as speculations are rife that at least one couple will call it quits.

Executive producer Steve Molaro recently revealed during an interview that all the relationships will enter uncharted territory in the finale episode. While some will embrace the changes in their lives, others won't be as comfortable.

Based on the synopsis of the episode, Sheldon will push Penny and Leonard to set a date for their wedding, while Amy complains about the slow pace at which their own relationship is moving. The episode will see Amy and Sheldon celebrating the fifth anniversary of their first date, and apart from kissing and confessing their love for one another, their relationship hasn't progressed much.

Elsewhere, Raj and Emily too think about where their relationship is headed, while Bernadette and Howard continue to adjust to a life without Mrs Wolowitz. They also start fearing if Stuart will become a permanent guest.

"Between Bernadette and Wolowitz, the more immediate and bigger question of where is everything going is, how much longer are we going to live in this house with Stuart? I suppose it might mean he's going to have to live in the back of his comic book store again, but those same thoughts [are] also touching on Koothrappali and Emily. Everyone is confronting all of those issues at the same time," Molaro told Entertainment Weekly.

The executive producer also added that the finale will end with multiple cliffhangers.

"The Big Bang Theory" season 8 finale airs Thursday at 8pm ET on CBS.