The proposal happened just as his girlfriend was posing for a photo between Chris Evans and Hayley Atwell. The actors looked even more shocked than the bride-to-be when her future fiance presented the ring.
"Today at #SLCC15 in the middle of a photo op with Chris and I, a man got down on his knee and proposed with a ring to his girlfriend," Atwell, 33, tweeted of the moment. "It was one of the most moving and beautiful things I have been witness to. Congratulations to you both. May you have a blissful future."
It was one of the most moving and beautiful things I have been witness to. Congratulations to you both. May you have a blissful future xx
Evans, 34, was also blown away by all the extreme fan interaction.
"Wow....I've had the most amazing time at #SLCC15. I've been to a few conventions before but I've never had the opportunity to interact with the fans on such a personal level," the Captain America star tweeted. "They shared some wonderful stories that I was honored to hear. I'm filled with a overwhelming sense of gratitude. Thank you to all of my loyal, sincere, loving, and passionate fans from the very bottom of my heart."
Evans added: "You've reminded me how gratuitously lucky I am. #weareallconnected."
Newly engaged Kelsey Jackson thanked the stars for participating in her proposal. "@HayleyAtwell @ChrisEvans thank you so much for being there. It was such a shock! You both are awesome! #iAmEngaged," Jackson tweeted.