'The Big Bang Theory's' Kaley Cuoco, fiance Ryan Sweeting step out after engagement, reveal massive ring

kaley-cuoco-ryan-sweeting-engaged-instagram.jpg Kaley Cuoco's swift engagement with tennis player Ryan Sweeting came as a bit of a shock to fans of the "Big Bang Theory" star, but the two certainly seem head over heels.

On Saturday (Sept. 28), the young couple were spotted out on a lunch date in Sherman Oaks, CA, just two days after it was revealed that Cuoco had accepted Sweeting's proposal. Walking hand in hand, Cuoco's massive engagement ring is certainly on display. (Check out the photos here, over at Us Weekly.) Quick proposal or not, would you turn that rock down?

"It's only been three months but she knows Ryan is the one," a source close to the actress tells Us Weekly. "When you know, you know."

Cuoco is clearly deep in love. Shortly after the proposal, she tweeted, "Flying high, I could literally touch the sky with you..."

What do you think about Cuoco's ring?
Photo/Video credit: Instagram