Giving the dental profession their best bit of PR since Julia Roberts flashed her pearly-whites comes this first look at Dr. Carl. Played by FULL HOUSE/ER alum John Stamos, the good doctor will first pop up in GLEE’s second episode of the season (“Britney/Brittany,” airing September 28) in the duel role of Emma Pillsbury’s (Jayma Mays) love interest and thorn in Will Schuester’s side.