The Big Bang Theory season 12 episode 12 live stream: Watch online

What happens when an ex shows up… and wants your boyfriend to be the father of his baby? Penny is about to find out this week on The Big Bang Theory.

This week’s The Big Bang Theory is all about exes but it may not be as bad as you think. When Penny’s ex-boyfriend Zach shows up, it isn’t Penny he needs to see… It’s Leonard. Per CBS’ synopsis for tonight’s episode, Zach apparently is infertile and needs Leonard’s help.

If that doesn’t sound strange already, a preview for this week’s episode offers a bit of insight. Apparently, Zach wants Leonard to be the “father” of his baby. Leonard is a genius, sure, so his DNA is pretty valuable. But Penny brings up immediately how absolutely awkward an ask that is.

Watch the preview here.

Penny is 100 percent right that this is not a normal situation, and Leonard should definitely consider how strange this would be in the long run. He and Penny don’t even have a child yet, so for him to let a somewhat stranger get his DNA for their kid is beyond weird.

As for the other ex situation this week, Koothrappali is trying to win his ex-fiancee Anu back. And he’s doing so a la Love Actually. Will those romantic note cards sway Anu? Or will she find it entirely creepy and push Koothrappali away?

We have a feeling these two will find their way back into each other’s arms — it is the final season after all, so resolutions are bound to happen (creepy cards or no creepy cards).

Here’s how you can watch The Big Bang Theory tonight:

"Date: Thursday, Jan. 10Start Time: 8 p.m. ETEpisode: “The Propagation Proposition”TV Channel: CBSLive Stream: Watch live on Fubo TV. Sign up now for a free seven-day trial. You can also watch on CBS’ live stream."

The Big Bang Theory‘s season 12 will be the series’ final run. Will you miss the show? Let us know in the comments!