UPDATE: Read on for the original story, but do check out the first promo clip too…
According to the apparently rather reliable TV By The Numbers, ABC have formally picked up the Marvel Movieverse spin-off, Agents of SHIELD, for a full season order.
What's more, they cite "reports" that the first promo will air during the season finale of Once Upon a Time.
That's this Sunday.
We'll keep you posted on any significant updates.
UPDATE: I said we'd keep you updated. IGN are calling the green light "official," though they're not citing any sources and there's no ABC press release I can see as yet.