Apparently in an interview at the 2014 PaleyFest with actress Chloe Bennett who plays the character of Skye on Marvel's Agents of S.H.I.E.L.D., she let the cat out of the bag in regards to the origins of the mysterious blue alien first seen in the episode “T.A.H.I.T.I.” According to her the alien belongs to the race known as The Kree.
In the episode it is revealed that the blood from this alien can be converted into a secret formula that can heal life threatening injuries. Both Skye and Phil Coulson (Clark Gregg) who was seemingly killed in the Avengers movie have been brought back from the brink of death using the mysterious serum concocted from this blue alien.
Now Bennett reveals the aliens origin very casually as if it is common knowledge. Someone might want to tell her it was a big mystery of the show and that she's ruined the surprise for the network, but never-the-less it would seem as if Kree have in fact visited the Earth previously in the Marvel Cinematic Universe.
For those not familiar with who the Kree are, in the comics they are a scientifically and technologically advanced militaristic alien race who first appeared back in Fantastic Four #65 which was published in 1967 by Stan Lee and Jack Kirby. Their arch-enemies are another alien race of shape-shifters known as the Skrulls.
We know that the Kree will have some type of role in the upcoming Guardians of the Galaxy movie from Marvel since we know Ronan the Accuser
who is Kree will be in that movie. Does this Kree alien showing up on S.H.I.E.L.D. foreshadow some type of upcoming connection between the TV series and that movie?
To see the full interview with Chloe Bennett see the video below from Fanboy Comics.