FULL AUDIO: Morrison and Harris Sing 'Dream On' on GLEE

Here's a preview from tonight's GLEE - "Dream On" - from the upcoming episode "Dream On", which airs on FOX on Tuesday, May 18 at 9pm.

Television's most award-winning new series, GLEE was recently honored with a Peabody Award; a Golden Globe for Best Television Series, Comedy or Musical; a Screen Actors Guild Award for Outstanding Performance by an Ensemble in a Comedy Series; and a People's Choice Award for Favorite New TV Comedy. The music from GLEE is an international sensation with "Glee: The Music, Volume 1" and "Glee: The Music, Volume 2" topping charts in Australia, the U.K., New Zealand, Ireland and Canada. In the U.S., over 4.5 million songs have been downloaded, and both albums have been certified Gold for sales in excess of 500,000 units.

GLEE follows an optimistic teacher who - against all odds and a malicious cheerleading coach - inspires McKinley High's Glee Club to conquer the world one singing competition at a time. GLEE stars Dianna Agron, Chris Colfer, Jessalyn Gilsig, Jane Lynch, Jayma Mays, Kevin McHale, Lea Michele, Cory Monteith, Matthew Morrison, Amber Riley, Mark Salling and Jenna Ushkowitz.