Two epic matriarchs meet for the first time on The Big Bang Theory season 8, episode 23.

The episode, titled “The Maternal Combustion,” will feature the return of Christine Baranski as Leonard’s mother Beverly, and Laurie Metcalf as Sheldon’s mother Mary.

On last week’s episode of The Big Bang Theory, Leonard delivered the commencement address at his high school over Skype, and enjoyed a minor epiphany about education. Meanwhile, Howard nearly lost his mind over trying to fix a helicopter drone for Raj, who played his parents off each other to get more money.

Parents will obviously be a theme in The Big Bang Theory season 8, episode 23, as the first sneak peek from the episode makes clear. Evidently, Sheldon and Leonard’s mothers do not hesitate to dive straight into serious subjects when they meet.

Seriously, we have no idea who is coming out on top of this one.

In the second clip, Bernadette finds that she is acting as a mother to Howard and his ridiculously slobby friends. (We definitely know who is coming out on top of this one.)

The third sneak peek from “The Maternal Combustion” sets up the arrival of Sheldon and Leonard’s mothers – and makes it clear that this is a pretty significant development for everyone involved.

The still photos from The Big Bang Theory season 8, episode 23 focus mostly on the mom-related portion of the episode, though we also get a few glimpses of the gang’s messy male members.

The Big Bang Theory season 8, episode 23, “The Maternal Combustion,” airs tonight at 8:00 p.m. on CBS.

What are your hypotheses for ‘The Big Bang Theory’ season 8, episode 23?