35 Nude videos. 4 Undress Celebs. Jaimie Alexander (born Jaimie Lauren Tarbush; March 12, 1984) is an American actress known for portraying Jessi on the TV series Kyle XY and Sif in the 2011 superhero film Thor, its 2013 sequel, Thor: The Dark World, and Agents of S.H.I.E.L.D.