The couple went public with their relationship earlier this month and the American actress announced their plans to marry shortly after.
"[He] actually started a little fight with me and threw me off," Cuoco told Entertainment Tonight. "I was like, 'Oh my God, things aren't great.' He surprised me at the end of the night [when] he popped the ring out. It was amazing."
Cuoco was rumoured to be dating Man Of Steel actor Henry Cavill in July.