MIDSEASON FINALE: In tonight’s new episode, Rebecca (Rachel Bloom) finally reunites with Greg, and he’s a new man. Or, at least, played by one. The character used to be portrayed by Santino Fontana, but, beginning tonight, is played by Skylar Astin from Pitch Perfect. And unlike the switch of the two Darrins on Bewitched in the 1960s, this time the swap is noticed. Sort of.