Kaley Cuoco Sparks Engagement Rumors After Stepping Out With Massive Diamond Ring

Big Bang Theory actress was seen running on set of a new film

Is Kaley Cuoco officially off the market?

Well, not so fast. The Big Bang Theory actress was seen running around a Los Angeles set wearing a massive diamond sparkler around her wedding ring.

And while things have been getting serious in her relationship with tennis star Ryan Sweeting, it could be that the bling is just for her upcoming role.

But let's investigate further, shall we?

The blond actress has been cast as the lead in the future flick The Wedding Ringer—a comedy centered around a loner who hires a stranger to pose as the best man at his wedding.

Cuoco could undoubtedly be sporting the gorgeous accessory for her bride-to-be character, but she could also not-so-subtlety be hinting that she and Sweeting are about to walk down the aisle themselves.

The two, who began dating earlier this summer, made their first red carpet appearance together at the 2013 Primetime Emmy Awards on Sunday evening.

The 27-year-old Instagrammed a photo of the night, writing, "#emmyweekend greatest date ever @ryansweething." OK, that's adorbs!

The actress was most recently linked to Man of Steel star Henry Cavill after the two went public with their very brief romance over the summer.

Before that, Cuoco dated musician Bret Bollinger as well as her Big Bang costar Johnny Galecki.