The 30-second tear-jerking clip shows the cast walking down the school's halls to a memorial of their late friend.
According to Yahoo TV, the episode begins with Finn already passed away but does mirror that of Monteith's death.
Monteith was found dead in his room on the 21st floor of the Fairmont Pacific Rim Hotel on Vancouver's waterfront in July. The British Columbia coroner later confirmed the actor died from combining heroin and alcohol.
The "Farewell to Finn" episode airs Thursday at 7 p.m. PST on Fox.