04/20/2013 05:46 pm ET Updated Apr 24, 2013

'The Big Bang Theory' Season Finale: Will Leonard And Penny Stay Together?

All's well right now on "The Big Bang Theory" as far as Leonard (Johnny Galecki) and Penny's (Kaley Cuoco) relationship is concerned.

But according to TVLine, the season finale will present Leonard with a huge obstacle: a job offer overseas.

“He's a little nervous, because he doesn't want anything to get screwed up," executive producer Steven Molaro said, adding that although Penny is supportive she would "very much ... miss him.”

The Leonard-Penny drama isn't the only excitement headed "Big Bang's" way, though: TV legend Bob Newhart is swinging by the series on May 2 as Professor Proton, a childhood hero of Leonard and Sheldon's (Jim Parsons).

"I specified 'Big Bang' because of the writing and the live audience," Newhart told TV Guide, noting that the last scene "sets it up for me to return a couple more times next season."

"The Big Bang Theory" airs Thursdays, 8 p.m ET on CBS.