When Fox's beloved musical dramedy returns from its hiatus in April, Gleeks are in for many spoilery surprises. At PaleyFest 2010, a celebration of television, Glee panelists brought in the biggest audience the festival has seen its 27-year history and creator Ryan Murphy dished about the second half of the season. Besides a song from Lady Gaga, who Murphy says is "arguably the most important pop star right now," star Matthew Morrison admitted he'll be sing Aerosmith and Billy Joel with Neil Patrick Harris on the April 13 episode. Jane Lynch additionally revealed that she sings "Vogue" in the upcoming all-Madonna episode. Also in store, Murphy says, next season will experiment with a new musical genre. "We are going to do an episode in the second season with all original music," he says.