'The Big Bang Theory' Season 10 Episode 1 spoilers: Penny deals with family troubles; Sheldon and Leonard may become stepbrothers

It’s only a couple of weeks before the much-awaited return of “The Big Bang Theory” on the small screen, and fans get another juicy teaser of what’s in store for the pilot episode of Season 10.

Earlier in August, CBS announced that it is beefing up comedy series’ cast with the addition of actor Dean Norris. He is scheduled to appear in a multiple episodes as Captain Williams, a tough Air Force representative from the Department of Material Command who’s interested in Howard (Simon Helberg) and Leonard’s (Johnny Galecki) quantum gyroscope for military applications.

Spoiler Alert! This article contains "The Big Bang Theory" Season 10 spoilers. Read only if you want to know more about it.

It looks like Leonard also has bigger things to worry about. Cinema Blend reports that on the first episode of “The Big Bang Theory” Season 7, Leonard faces an awkward encounter after his dad Alfred (Judd Hirsch) spends a night with Mary (Laurie Metcalf), Sheldon’s (Jim Parsons) mum. Fans would remember that the two oldies went for a night cap after Leonard and Penny’s pre-wedding dinner.

There’s a huge possibility that Alfred and Mary went just beyond sharing drinks. After their little “night cap” the two may have slept together, which explains the awkward morning the next day. This development may also have triggered the rumours that Leonard and Sheldon could end up being stepbrothers. However, creators of “The Big Bang Theory” haven’t confirmed these reports.

Speaking of parental problems, spoilers also suggest that Penny (Kaley Cuoco) faces her own family drama. Fans will finally meet Penny’s mum and brother, and true to “The Big Bang Theory” signature, they would be anything but ordinary. “Sons of Anarchy” actress Katey Sagal will be introduced this season as Penny’s mum, Susan, while Jack McBrayer from “30 Rock” will play Randall.

According to the show's producers, who confirmed this storyline at Comic-Con 2016, Susan can be described as “stressed out and neurotic from a life dealing with her troubled—yet cheerful—son, Randall.” It turns out Penny’s big brother is a drug dealer and ex-con.

Fans are excited how these new characters create their rapport with other “The Big Bang Theory” cast members, including Raj (Kunal Nayyar), Amy (Mayim Bialik), Bernadette (Melissa Rauch) and Emily (Laura Spencer).

“The Big Bang Theory” Season 10 is set to premiere in the US on Sept. 19 on CBS. Stay tune for more "The Big Bang Theory" spoilers.