Read on for the spoilers we've learned:
The producers have promised that you will see some Once characters crossing over into the world of Wonderland. I've watched the entire first episode, and I can tell you that you'll see two right away! My only hint is that one of them is someone who Once fans have been dying to see again.
Source: TV Guide
The pilot of Wonderland airs on Thursday, Oct. 10 at 8 PM on ABC.