On tonight's episode of The Big Bang Theory, "The Cohabitation Experimentation," Sheldon (Jim Parsons) and Amy (Mayim Bialik) are moving in together, which means Penny (Kaley Cuoco) and Leonard's (Johnny Galecki) awkward third wheel is finally out of the apartment. They look pretty broken up about it, don't they?

Kaley Cuoco and Johnny Galecki, <em>The Big Bang Theory</em>Kaley Cuoco and Johnny Galecki, The Big Bang Theory

Just kidding! They do a pretty normal thing for couples to do when they have the place to themselves — have an underwear dance party. It's a celebration!

It remains to be seen, however, if Sheldon and Amy's experiment works out. I have a feeling Penny and Leonard's joy will be short-lived when Sheldon gets homesick.

The Big Bang Theory airs Thursdays at 8/7c on CBS.

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