Thankfully I am still awake at this time. This just in: SpoilerTV reports that Lost's Dominic Monaghan is indeed joining the cast of ABC's new series, FlashForward.
Speculation that Monaghan is joining the series began when he popped up on a network promo plugging ABC's fall lineup. While initially network reps denied that he is returning to Lost, it was confirmed that he is joining a new show on the network, which turned out to be Flash Forward, a series where people around the world deal with the catastrophic effects of a two-minute blackout--and is touted as a successor to Lost, which is wrapping up its run next year.
At the same time, speculation also arose that Monaghan is returning to Lost, after he was spotted meeting with show executives, and numerous rumors spread across the Internet. While there's no official word on whether the already-dead Charlie will be revived, it seems they're heading towards that direction.
SpoilerTV reports what was previously reported around a month ago: Monaghan will appear on the series beginning from its second episode. His character is named Theo, and he has started production. His co-stars include Joseph Fiennes, John Cho, Sonya Walker and Jack Davenport.