'GLEE' goes 'GREASE' with 'Summer Nights' cover

Now that Sam has returned to McKinley High and "Glee" is addressing his summer romance with Mercedes, it seems pretty fitting that the former couple would cover the most famous showtune about seasonal loves -- "Grease's" "Summer Nights."

The "Glee" version, which just leaked online, is pretty faithful to the original, with the respective New Directions members spilling all to their groups of friends.

Check out the tune before it's pulled from YouTube.

How excited you are for "Glee" to go "Grease" on Tuesday, Jan. 17?