Physical (Glee Cast Version) (feat. Olivia Newton-John)

You know how at the end of the movie Grease Olivia Newton-John transforms from a chaste good girl into a leather-clad vixen? She was definitely in vixen mode for this song, which if you are at all paying attention to the lyrics, is blatantly about sex: "There's nothin' left to talk about unless it's horizontally." Olivia's real-life image was far more modest than what she portrays in this song, and she was concerned about how she would be perceived. Her managers talked her into recording it, as they knew they had a huge hit on their hands.

Songwriters Steve Kipner and Terry Shaddick came up with this song, which was originally titled "Let's Get Physical." Instead of writing about the emotions of love, they decided to write this about the physical side, which many listeners found very refreshing in a pop song. Other songs Kipner helped write include "Hard Habit To Break" by Chicago and "Genie in a Bottle" by Christina Aguilera.

The song was released about a month after MTV went on the air, so the video got a lot of spins on the new channel. In the clip, Newton-John is shown teasing fat men as they try to exercise in some kind of locker room/gym. The whole idea of the video was to distract from the fact that the song is about sex, and fat guys working out accomplished that goal. Aerobics was just gaining popularity when the song came out, so the video jumped on the trend and included some scenes where Olivia leads a cardio routine the guys can't handle. Eventually, the schlubs are replaced by fit, muscular men who ignore Olivia and pair off, indicating that they are gay. Despite the lascivious themes, the video was a huge commercial and critical hit - it won the Grammy for Video of the Year.