Big Bang Theory season 10
Penny with her mother-in-law Beverly in The Big Bang Theory CBS

The Big Bang Theory season 10 returns with new episodes on 19 September wherein fans will get their first glimpse at Penny's mother Susan (played by Katey Sagal), and brother, Randall (played by comedian Jack McBrayer).

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Executive Producer Steve Molaro spoke to Entertainment Weeklyabout Penny's family and hinted at tension between Leonard's wife and Susan. He said, "Penny's close with her dad." Keith Carradine played Penny's dad, Wyatt and have made several appearances in the show.

According to Molaro, Penny's dad will be caught between his wife Susan and daughter Penny's arguments. "As we know, her brother Randall has been a bit of trouble over the years, selling drugs and being in and out of jail, and that's put a lot of stress on her mom," the showrunner said.

He concluded by adding, "You will pick up on the tensions between her mother and her brother very quickly, and you get a glimpse of Penny and her dad being caught in the middle of that."

The hit CBS show is currently filming its 10th season, and the first promo featuring Sheldon Cooper, Leonard Hofstadter, Penny, and their elaborate family is expected to be released soon.

Here is the full synopsis of The Big Bang Theory season 10 premiere episode released by CBS Network:

In The Big Bang Theory's season premiere, after Sheldon's mother and Leonard's father share an evening together, everyone deals with an awkward morning the following day. Also, Penny's family arrives for the ceremony, including her anxiety-ridden mother, Susan (guest star Katey Sagal), and her drug dealing brother, Randall (guest star Jack McBrayer).