Big Bang Theory season 9 finale
Leonard and Sheldon's family and friends gather for a dinner in The Big Bang Theory season 9 finale CBS

A chaotic family reunion and a romantic cliffhanger awaits fans in The Big Bang Theory season 9 finale. Episode 24 is titled, The Convergence Convergence, where Leonard Hofstadter's recently-divorced parents Alfred and Beverly, and Sheldon's mother Mary Cooper will attend Leonard and Penny's "wedding ceremony".

The official synopsis of the finale episode reads as follows:

Click here to watch the episode via live stream online on CBS All Access. You can also click here to watch it online (only in the US).

Comedian Judd Hirsch will debut on the show as Leonard's father Alfred, who is in town to attend the ceremony. Senior Hofstadter will come face-to-face with his ex-wife Beverly and meet Sheldon's mother, Mary, thereby setting the stage for an awkward family moment.

Showrunner Steve Molaro spoke to The Hollywood Reporter about Alfred's dynamics with Leonard, and his ex-wife Beverly and teased an unexpected attraction.

Molaro said, "It's great to see the dynamics between him [Alfred] and Leonard, which is all new. There is a pretty acerbic and unpleasant relationship with him and his ex-wife Beverly, [and] Leonard. As far as what is surprising about that, there might be a bit of an unexpected attraction springing up between Leonard's father and Sheldon's mother."

The showrunner also teased a typical cliffhanger ending and shared, "We leave [the season] in typical Big Bang fashion — on bit of a cliffhanger with Leonard, Penny and Sheldon in the living room making sense of everything that's going on."

To know how the season ends, watch the finale episode that airs on 12 May on the CBS Network.