Fans are, of course, hoping the twist will be explained as the comic book series, titled Captain America: Steve Rogers, progresses.
It is not just fans who have expressed their outrage towards the twist; Captain America actor Chris Evans expressed his shock on Twitter.
Captain America recently found himself at the centre of fan campaign #GiveCaptainAmericaABoyfriend, Tweeters hoping Marvel Studios will give Cap a boyfriend at some stage.
Although Stan Lee created hundreds of Marvel characters, one of the few tentpoles he didn’t have a hand in creating was Captain America.