Cook posted a video from just after the proposal, with Cuoco in tears with the engagement ring on her finger. There was just one problem: she hadn't said yes yet!
"Honey, how do you feel? Honey?" Cook is heard asking her. "What's on your finger honey?"
"We're engaged," Cuoco says, crying.
"You still haven't said yes, yet!" Cook says.
"Yes! I say yes, I say yes," she says as the video ends.
"Who knew my prior post was oracular," Cook wrote in the caption, referencing a photo he took of the couple at a Target. "Well after nearly two years I finally got up the courage to ask her to marry me. This is the best night of my life and I think the video shows it is the best night for Kaley as well.....of she said yes!!!!!"
Cook also posted a photo of the engagement ring, thanking jeweler Nadis Diamonds.
This will be Cuoco's second marriage. She was previously married to tennis player Ryan Sweeting for just over a year, from December 2013 to September 2015. She was also engaged to Josh Resnik, but they split before the wedding in 2012, PEOPLE reported at the time.
As E! News points out, she started dating Cook in March 2016 and made their first red carpet appearance together in September 2016. Cook is an equestrian, whose family runs Pomponio Ranch.