Big Bang theory season 8  finale
The Big Bang Theory season 8 finale will feature series-changing decisions CBS

The Big Bang Theory returns with a new episode on 23 April at 8pm on the CBS Television Network.

Episode 22 is titled The Graduation Transmission, where Leonard gives a commencement address at his former high school.

Click here to watch the episode via live stream online on CBS Go or click here to watch the episode online.

According to the official synopsis, "Wolowitz questions his engineering abilities when he and Sheldon can't get a toy drone to fly. A cancelled flight nearly prevents Leonard from giving the commencement address at his former high school. Raj pits his parents against each other when his father cuts him off financially."

TBBT season 8 finale

Spoilers for The Big Bang Theory season 8 finale suggest new things for its couples - Leonard and Penny, and Sheldon and Amy.

It has been five years since Amy and Sheldon went on their first date, and a new report suggests that Amy will push her boyfriend for more in the season 8 finale.

But before he takes the next step, Sheldon pushes Leonard and Penny to take their next step, which involves setting a wedding date.

Executive producer Steve Molaro told TV Guide, "Sheldon has progress and relationships on his mind and wants to know just in fact why Leonard and Penny going so slow."

"If they're an example of who's progressing, why don't they have a wedding date?" By episode's end, all four will "make life-changing and series-changing decisions about their relationships," Molaro teased.