'The Big Bang Theory' premiere: One giant leap for Sheldonkind

big-bang-theory-s4-premiere.jpg"The Big Bang Theory" is taking a huge step as its fourth season begins.

We're not talking about the show's new Thursday-at-8 timeslot, although that's a pretty big deal too. No, this is more momentous: Sheldon is going on a date. The proof is right there at the top of the post.

Mayim Bialik is reprising her guest role from last season's finale as Amy, Sheldon's ( Jim Parsons) seemingly perfect match. The Season 4 premiere will test that idea right off, as the two go on a date, Sheldon's first ever.

And, oh yeah, Penny ( Kaley Cuoco) finds herself playing the third wheel -- and judging by her expression in the photo above, she's none too thrilled at the dinner-table conversation.

"The Big Bang Theory" starts its fourth season at 8 p.m. ET Thursday, Sept. 23. The episode is called "The Robotic Manipulation, which we're guessing has something to do with what Wolowitz ( Simon Helberg) is up to in the picture below.

big-bang-theory-wolowitz.jpgPysched to have "Big Bang" back? What do you think of the new timeslot, and of Amy's continued presence?

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Photo credits: CBS