It was previously reported that the pair had teamed up with Lost co-creator Damon Lindelof to produce the new show.
Variety now reports that Once Upon a Time has been sold to ABC and will present "a modern-day take on fairy tales, with a female protagonist who comes from a unique background."
The project will be set in present-day Maine and will feature a large ensemble cast. It is also said to combine elements of science-fiction and fantasy.
Once Upon a Time is now in development by ABC for the 2011-12 season.