Kaley Cuoco teases 'Big Bang' Halloween episode with Johnny Galecki throwback photo collage

Kaley Cuoco recently treated "Big Bang Theory" fans to a glimpse of the show's Halloween episode by sharing a few throwback photos with her co-star, Johnny Galecki in an Instagram collage.

Before the hit sitcom aired on Thursday, Cuoco took to social media to tease the night's Halloween episode.

In the post, the actress shared a side-by-side photo collage of her and Galecki featuring two images. The first photo showed the pair from Season 1 and the second was a still of the couple from the current season. In both photos, the stars are clad in costumes from the show's yearly Halloween episodes.

In the Instagram caption, Cuoco wrote, “From a Season 1 kitty kissing a hobbit, to a Season 12 barmaid married to Inspector Gadget. don’t miss and (sic) all NEW @bigbangtheory_cbs Halloween episode tonight!”

Sadly for "Big Bang" fans, Thursday night's episode will be the show's final Halloween show as the beloved series announced this year that Season 12 would its last.

But while the famous cast is still on the air, they are still making millions.

It's been a big week for the "Big Bang" cast as it was revealed on Wednesday that all four of the male co-stars -- Galecki, Jim Parsons, Simon Helberg and Kunal Nayyar -- topped the list of the highest-paid actors on TV.

According to Forbes, Parsons landed the No. 1 spot making a total of $26.5 million, with Galecki falling behind in the No. 2 spot earning $25 million. Helberg and Nayyar were tied at No. 3 both making $23.5 million.

And like her male co-stars, Cuoco appeared on the highest-paid TV actresses list in the No. 2 spot, making $24.5 million.

The "Big Bang" actress fell behind "Modern Family" star Sofia Vergara who took the No. 1 spot earning $42.5 million.