Before Marvel's Agents of S.H.I.E.L.D. headed to ABC this week, Marvel pillaged ABC for a S.H.I.E.L.D. agent when they brought Revenge star Emily VanCamp to star in Captain America: The Winter Soldier.
Her role? Reportedly to be Captain America's romantic interest--which many took to mean that she was Sharon Carter, S.H.I.E.L.D.'s "Agent 13."
Of course, Sharon was created at a very different time in comics, and Captain America, having been encased in ice for a generation, woke up to find himself dating the younger relative of his previous belle, Peggy Carter (played in Captain America: The First Avenger by Hayley Atwell). She was a pretty standard-issue female spy for much of her existence, although when she was reintroduced by Mark Waid following Captain America's apparent return from the dead in the '90s, she had a much harder edge, blaming Cap for desserting her.
She was given yet another charaterization tweak during the Ed Brubaker run, when she was presented as a more sensitive character and unambiguously Cap's romantic foil for the first time in years (during the Waid and Dan Jurgens runs, she had a kind of semi-adversarial on-again/off-again romance). Most recently, she apparently died while accompanying Cap on a mission, and there's some speculation that the Agent 13 of the movie might not be Sharon at all, but another female operative who uses the same codename (that might be a bit less awkward than just replacing Peggy with her niece).
"There are so many different versions of the character, so really what you have to do is sort of take all of that information and make it your own and hope that the fans like it," said VanCamp in a recent interview. "It's a little bit of a gamble, and it's a little bit nerve-wracking at times, but that's also part of the fun."
She added, "Researching my character, I started to get interested in a lot of other things that I was reading. It was just a really fun process."
What her role might be in future movies, and whether she might appear on Agents of S.H.I.E.L.D., she was noncommittal.