Is it deja vu or...
Hasn't this show been on before? Like a year or so ago, and with a different cast?
"Flash where have you been?"
"Where haven't I been! Wooof!!"
They premiered the first episode back in August, just as a preview. Now they are going to show the full season. It wasn't a different cast. It's the same cast. Same show.
That's probably what you are thinking about.
http://30.media.tumblr.com/tumblr_lxpbbc4gyy1qzqvqoo1_500.jpg