'The Big Bang Theory' season 9 spoilers, season 10 news: Leonard's parents and Sheldon's mother clash, tenth season to mark the end of the series?

Hit American sitcom "The Big Bang Theory" season 9 will come to a close tomorrow, and the finale is expected to end on yet another cliffhanger.

According to the official synopsis for tomorrow's episode titled "The Convergence Convergence," Leonard Hofstadter's (Johnny Galecki) parents Alfred (Judd Hirsch)
and Beverly (Christine Baranski) will visit him. However, chaos ensues when Sheldon's religious and conservative mother Mary (Laurie Metcalf) also comes to town. Meanwhile, Howard Wolowitz (Simon Helberg) and Raj Koothrappali (Kunal Nayyar) are worried that the government will track them down after they were contacted about their guidance system.

Guest stars for the upcoming episode include Judd Hirsch to play the character of Alfred Hofstadter and Marcus Folmar as a police officer. Actresses Christine Baranski and Laurie Metcalf return to reprise their roles as Beverly Hofstadter and Mary Cooper, respectively.

With the ninth season concluding tomorrow, fans are anxious to know when their favorite show will return with all-new episodes. In a previous interview, showrunner Steve Molaro mentioned that season 10 might be the end of the line for the hit series. "I can't speak to the future or on behalf of the cast or where we'll be then but it's certainly possible that it could go past that," Molaro told The Hollywood Reporter. "The reality is that maybe season 10 is the ending point. The real answer is I don't know and all I can do right now is go episode to episode and try to make each one the best that we can. There's still so many episodes to go. Even if hypothetically season 10 was the end, I wouldn't be focusing on that yet. That seems like something that would be dealt with way down the line."

Co-creator Chuck Lorre also gave his take on the show pushing through, saying, "I never imagined nine [seasons] and here we are. I'm not going to presume to know how many years this has because it's ridiculous for me to guess. It's already gone beyond my wildest dreams so anything beyond this ... as long as everybody is having a good time and we're making a show we're proud of ... then it's worth continuing."

Catch the season 9 finale of "The Big Bang Theory" which airs tomorrow, May 12 at 8 p.m. on CBS.