As played out in the trailer: Kurt Russell will portray Ego: The Living Planet, and the character has been confirmed as having fathered Peter Quill, aka Star-Lord.
The question of who Star-Lord’s father actually is dropped as a key story point at the end of Guardians of the Galaxy, but was left to be answered in the now-forthcoming sequel.
Traditionally portrayed as a (literal) planet whose topographical features form a human face, Ego is a cosmic being from deep space who frequently serves as both a villain, mentor and morally-ambiguous figure in the vast Marvel cosmology.
Apart from fathering the franchise’s hero (somehow), Ego’s form and function in the Marvel Cinematic Universe is unknown – although one of his lines in the trailer (not yet online) is said to have been: “Yes, Drax, I do have a penis.”