'Glee' Music Preview: Hear Mercedes and Sam Sing 'Summer Nights' from 'Grease!'

True, it's still going to be a couple of weeks until "Glee" returns with new episodes. But if you're itching for some new "Glee" content, we have you covered!

A full song from the upcoming episode "Yes/No" has been released online, and it's a classic... if you're a musical theater type. It looks like Ryan Murphy is trying to stick to the promise of more classics and less current pop with a cover of "Summer Nights" from "Grease."

But if you're a fan of the pop stuff, fear not: the episode will also feature "We Found Love" by Rihanna and "Moves Like Jagger" by Maroon 5.

Mercedes (Amber Riley) and Sam (Chord Overstreet) take on the singing duties with "Summer Nights," which makes it fairly clear that the short-lived romances between Mercedes and Sam might see a rekindling as this season goes on. The two were set up for a relationship storyline at the end of season two, but when Overstreet was demoted from series regular, he dropped out of the show for the first half of season three and the storyline went kaput.

Check out "Summer Nights" as sung by "Glee" cast members Chord Overstreet and Amber Riley below: