There's a lot to look forward to in Thursday's all-new episode of "The Big Bang Theory," as both Sheldon and Leonard's mothers will come to town and finally meet each other.

In the next episode, which is titled "The Maternal Combustion," "McCarthys'" Laurie Metcalf will reprise her role as Mary Cooper, Sheldon's mother, while "The Good Wife" star Christine Baranski will return as Beverly Hofstadter, Leonard's mom. Although the actresses have appeared on the show in the past, Thursday will mark the first time that the two moms have guest starred in the same episode.

According to The Hollywood Reporter, the moms will finally get to meet since they will both be in town to celebrate their sons getting a science award.

A preview of the season's penultimate episode reveals that Leonard's mother, who is a master of psychology, will continue her bizarre interest in studying Sheldon.

It will also be interesting to see how the two women get along since they come from very different walks of life and do not have much in common when it comes to child rearing, notes Carter Matt.

"You've got a highly intelligent, cold-hearted psychiatrist in Beverly, and a warm, loving and God-fearing woman in Mary -- and both of them are not afraid to speak out," executive producer Steve Molaro told TVLine, adding that the pair end up "doting on Sheldon" and "pushing Leonard off to the side."

In the meantime, Bernadette will come to the realization that Howard, Raj and Stuart have "transformed into what feels like her three teenage sons," teased Molaro. "She's had enough of it and starts giving them chores to do."

The showrunner also dropped spoilers about the Season 8 finale, revealing that Amy will become frustrated with her slow-moving five-year relationship with Sheldon and present him with an ultimatum.

"She's fed up with how slow their relationship is progressing over the past five years," explains Molaro. "So she puts him up against a wall and says, 'What are we doing?'"

In response, Sheldon points out that it's been over a year since Leonard and Penny got engaged, yet they have no set wedding date in order to divert some of the pressure.

"He goes, 'You two haven't picked a wedding date yet. Why not?' So that comes to a head, too," said Molaro.

"It has been five years, and even though things have been progressing, for Amy, it's still, for her, not quite at the speed she'd like, so she really starts pushing back, and he's got relationships on his mind because of that," Molaro told THR. "He wants to know why he's getting grief about moving slowly, where if Leonard and Penny are an example of a couple moving forward, they've been engaged for over a year and can't even pick a date. So he starts poking at that and making them ask themselves the same questions. Both of those couples -- Sheldon and Amy and Leonard and Penny -- make some huge, life-changing decisions."

This will also force the engaged couple to confront the truth behind their non-existent wedding date.

"Penny and Leonard would tell you the reason is she's busy with her new career and things are really great between them and they're in no rush," explained the EP to TVLine. "But, underneath it all, what's the real reason? That all comes out. The show has always been Leonard and Sheldon, our single bachelors living in that apartment," reasons Molaro. "But we're going right into the heart of that at the end of the season."

Season 8, Episode 23 of "The Big Bang Theory," "The Maternal Combustion," will air on Thursday, April 30 on CBS.

Watch a preview below.