With the season finale of The Big Bang Theory finally here, the question on the tip of everyone's tongue is: Who's leaving? As history repeats itself, at the end of each season a cast member leaves for one reason or another, and this time it's Leonard's turn as he embarks on a four-month-long sea excursion with genius Stephen Hawkings. ET caught up with the cast to get to the bottom of what fans can expect for the future of the series and whether a potential spinoff might be in the works.
"It's exciting, but it's a little concerning too because things are going so well with Leonard and Penny to go away to a place where she can't visit for those four months," says Johnny Galecki of his character, Leonard Hofstadter, an experimental physicist.
After six years of an on-again, off-again relationship with blonde beauty Penny, played by Kaley Cuoco, the shared sentiment among the cast is that the long distance might threaten the budding couple's future together, but Kaley and Johnny remain steadfast that their onscreen love is stronger than that.
"Finally, after six years we can say they are good. So hopefully it doesn't rock the boat too much," Cuoco adds. Penny remains supportive of Leonard's decision to take up the research endeavor, but one character who is less than happy about Leonard's new success is Sheldon.
"It's a good opportunity for him and a good opportunity for anyone else is a bad thing for Sheldon," jokes Jim Parsons, who portrays Sheldon on the show.
Sheldon's main motivation is that he will miss his best friend and he proceeds to try and discourage Leonard from going on the trip by attempting to convince him that being out in the North Sea can be dangerous with risks of "drowning and sharks." Leonard remains unimpressed until Sheldon plays the "girlfriend" card and reminds him that being away for so long could damage Leonard's relationship with Penny.
With Leonard's exit, the question of whether he will be back for the next season hangs in the air.
"I hope he comes back," joked Mayim Bialik, who plays Sheldon's equally socially awkward girlfriend Amy.
"It could be a spinoff. Not that I've heard about, but I'm saying there could be. That would be a possibility," hypothesized Parsons.
Another theory jokingly going around set is that Leonard could possibly be killed off.
"It would be easy to kill anybody off during our hiatus, wouldn't it?" joked Simon Helberg, who plays Howard Wolowitz.
"Let's see if Johnny comes back," said Kunal Nayyar, who plays Raj. "Maybe he's doing his own show?"
"I remember when he read that [the departure] at the table read. He said 'so what's happening to my character next year? Lost at sea?'" laughs Nayyar of Galecki's fleeting concern that he might be written out of the series.
To find out if Leonard heads out to sea, tune in to the finale episode of The Big Bang Theory, which airs May 16 at 8 p.m. on CBS.
For a sneak peek of "The Bon Voyage Reaction" episode and interviews with the cast, check out the video above.