The blonde actress, who plays waitress Penny on the sitcom, was photographed gazing at her tennis player beau as they walked the red carpet at the Fourth Annual Veuve Clicquot Polo Classic in Los Angeles on Saturday (5 October).
Kaley and Ryan announced their engagement at the end of September, just three months after they started dating.
27-year-old Kaley has admitted that she understands why some people could think they're moving too fast, but she knew from the minute she met Ryan that he was the one.
She told ET Online: "We have all the same family friends," she explained. "We grew up with the same people, we just never met. So I kind of feel that I've known him my whole life. I know that it seems a little crazy on paper, but it's what works for us."
Kaley looked beautiful at the weekend's polo event, wearing a monochrome dress and black heels and, of course, her gorgeous engagement ring!
The actress has been busy working on the set of new movie The Wedding Ringer, about a man who provides best man services for guys who have no close friends or family to take on the role.
For Kaley, however, she isn't planning her own wedding anytime soon. According to Us Weekly she told reporters at the polo event: "We are too busy to wedding plan. In a year we will start talking about it. We are enjoying being engaged."
More celebrities who are engaged in pictures!
Copyright: Instagram Mark Wright