Joe Fergus, 24, from Mold in Flintshire, and Robert Brookes, 21, from Nottingham, were photographed outside Chester's Storyhouse theatre.
Posting the image on Facebook, Mr Fergus said: “When haters be hating, the best thing to do is spread the love.”
The image was later shared on the social media outlet by Chester Pride, prompting an outpouring of support.
Protesters had gathered outside the musical on Tuesday, holding banners with messages like “Flee from the wrath to come” and “Be sure your sin will find you out”.
When the couple started kissing, a crowd reportedly gathered and erupted into applause.
Explaining their decision to kiss in response to the protesters, Mr Fergus wrote on Facebook: “Lots of people were arguing with them, but honestly believe the best way to respond is with love.”
One social media user responded by saying: “I really didn’t think people could protest like that any more, it’s shocking. Well done boys."
Another said: “I absolutely love this!! Let the haters hate! You show them you beautiful pair.”
The Storyhouse theatre tweeted following the protests and said: “Storyhouse is and always will be a safe space. We celebrate and support LGBTQ+ communities - always. Let's have a FABULOUS night & week.”