The cast of
The entire cast of "The Big Bang Theory" posing for the camera.Reuters

The Big Bang Theory returns this September on CBS with the highly anticipated Season 8.

Last season ended with Penny and Leonard getting engaged and Sheldon leaving on a train to "find himself." Fans are excited about seeing Leonard and Penny, as the 'groom and bride-to-be' and rumours are doing the rounds that Lisa Kudrow, popularly known as Pheobe in Friends will appear in Season 8 as Penny's mother.

In an interview with TV Line, Kaley Cuoco, who plays Penny, hinted at the possibility of Lisa Kudrow, joining the cast as Penny's mother.

"I don't know what they're going to do, but I have always thought - and I hope this doesn't offend her (Lisa Kudrow) because I know she's super young, though we know Penny's mom got knocked up very early, -- that Lisa Kudrow would be so perfect. I've said that for years. I think it would be hilarious, plus I'm a huge fan of hers, so it's a selfish wish."

Another question that all fans are asking: Is Sheldon leaving for good?

According to TV Line, Jim Parsons said, "I never thought of that, but you're right — he could show back up at home immediately, couldn't he?" He also said that he grilled his bosses about where his alter ego will go, but no one told him, "I don't know if they know yet. They may know, but I really don't know if they do."

Parsons also teased about a possible "bedroom" romance between Sheldon and his love interest in the show, Amy Farrah Fowler, played by Mayim Bialik.

"I don't know that we're headed for the bedroom or the altar any time soon. But, whatever... The writers have been so good with the pace of it, just bring more is all I would say."

The Big Bang Theory's Executive producer Steve Molaro told Entertainment Weekly that his goal is to "chip away at Sheldon and break him down to the point where he just needed to leave to process everything."

Will fans get to see a Leonard-Penny marriage this season?

Kaley Cuoco, told TV Line that marriage is definitely on the cards this season. She said, "If I could write it myself, I think Leonard will me more of the bride, because I think it would be funny if he were the planner."

The star went on to say that Penny is not really suited to plan the wedding and that the "wedding planning" should be given to Leonard. "Penny is so aloof, she'd be a lot more easy-going than Leonard," added the actress.

There will be many surprises for fans this season. The show premieres on September 22nd on CBS.