Fox has decided to combine the 20th and 21st episodes of season three - in which New Directions travel to Chicago for the Nationals - into one.
According to TV Line, the first part of the episode sees Tina (Jenna Ushkowitz) experience an alternate reality after suffering a head injury in rehearsals.
The alleged plot fits with spoiler pictures that emerged last week showing Puck (Mark Salling) and Finn (Cory Monteith) dressed in outfits more suited to Blaine (Darren Criss) and Kurt (Chris Colfer).
It has been confirmed that next week's episode of Glee will be a Whitney Houston tribute and the following installment will feature a domestic violence storyline.
Glee continues Tuesdays at 8/7c on Fox. UK viewers can watch it Thursdays at 9pm on Sky1.
Watch the Glee cast's performance of 'How Will I Know' below: