Chris Evans and Hayley Atwell Become Part of Surprise Proposal During Meet-and-Greet at Comic-Con

The "Caption America" co-stars had no idea what one fan was planning.

The "Captain America" co-stars realized they had become a major part of one couple's love story when a fan dressed as Captain America bent down on one knee to propose to his Black Widow-costumed girlfriend in the middle of a photo op with the actors.

Evans and Atwell looked just as surprised as bride-to-be, Kelsey Jenkins, as her fiance presented her with the engagement ring.

The entire proposal was caught by the meet-and-greet photographer's camera, and Jenkins posted the photo to her twitter account, thanking Evans and Atwell for being there and saying the proposal was "such a shock."

While he didn't address the proposal directly, Evans, 34, reflected on his entire Salt Lake City Comic-Con experience in a series of tweets, thanking fans for reminding him how "gratuitously lucky" he is.

"Wow....I've had the most amazing time at #SLCC15," Evans wrote. "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.

"They shared some wonderful stories that I was honored to hear. I'm filled with an overwhelming sense of gratitude. Thank you to all of my loyal, sincere, loving, and passionate fans from the very bottom of my heart."

@HayleyAtwell @ChrisEvans thank you so much for being there. It was such a shock! You both are awesome! #iAmEngaged pic.twitter.com/23CGf6dCum

— Kelsey Jenkins (@kelseyjenks) September 28, 2015

Atwell, 33, opened up about witnessing the proposal on Twitter, describing the moment as "moving and beautiful"

Jenkins replied to Atwell's tweets, saying she wants to send Atwell and Evans invitations to her wedding.

The bride also revealed on Twitter that Evans was especially surprised during the proposal.

@Direforce @CaptainAmerica @HayleyAtwell @ChrisEvans he actually was saying, "Is this real? Is this actually happening right now?"

While he didn't address the proposal directly, Evans, 34, reflected on his entire Salt Lake City Comic-Con experience in a series of tweets, thanking fans for reminding him how "gratuitously lucky" he is.

"Wow....I've had the most amazing time at #SLCC15," Evans wrote. "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.

"They shared some wonderful stories that I was honored to hear. I'm filled with an overwhelming sense of gratitude. Thank you to all of my loyal, sincere, loving, and passionate fans from the very bottom of my heart."

While he didn't address the proposal directly, Evans, 34, reflected on his entire Salt Lake City Comic-Con experience in a series of tweets, thanking fans for reminding him how "gratuitously lucky" he is.

"Wow....I've had the most amazing time at #SLCC15," Evans wrote. "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.

"They shared some wonderful stories that I was honored to hear. I'm filled with an overwhelming sense of gratitude. Thank you to all of my loyal, sincere, loving, and passionate fans from the very bottom of my heart."