'The Big Bang Theory' season 10 release date, plot spoilers: Meet Penny's family; Upcoming season last for series?

A fall premiere has been scheduled for "The Big Bang Theory" season 10, and before it goes underway, the producers of the show want fans to meet Penny's family who would figure much in the upcoming installment.

Producers Steve Molaro and Bill Prady attended the San Diego Comic-Con with cast member Melissa Rauch, who plays Bernadette in the series. There, they talked about guest stars who would grace the tenth season and presented some teasers for the show.

Prady and Molaro told TV Line that Penny's (Kaley Cuoco) mom would appear on the show, considering Penny's wedding is one of the main arcs of the upcoming season. Penny's mom would be played by Katey Sagal of "Sons of Anarchy" and "Married with Children."

Aside from the mom, Penny's brother Randall (Jack McBrayer), a drug dealer who has just gotten out of jail, would also be showing up for season 10. According to Molaro, Penny's family would appear in the season premiere to give viewers the chance to get to know them better.

Cheat Sheet noted that Sagal and McBrayer's entry to the show is the latest in a slew of introductions. In season 9, Sheldon's (Jim Parsons) Meemaw (June Squibb) and Leonard's (Johnny Galecki) dad (Judd Hirsch) were introduced in the series.

In fact, Hirsch's character was a significant part of season 9's cliffhanger of an ending, when his character went missing with Sheldon's mom (Laurie Metcalf) during Penny and Leonard's pre-wedding dinner, making fans speculate that something's going on between the two.

There are speculations that these characters are being introduced, perhaps to tie up certain ends, because season 10 is going to be "The Big Bang Theory's" last. However, Molaro debunked the rumors, saying it's too early at this point to be talking about a series finale.

"The Big Bang Theory" season 10 will air on Sept. 19 at 8 p.m. EST on CBS. Keep coming back for more news and updates on series.