But didn't the fifth season of "Glee" end with Kurt (Chris Colfer) and Blaine seemingly happy together?

In the show's Season 5 finale "The Untitled Rachel Berry Project," fan-favorite couple Klaine performed together at a glitzy showcase for the rich socialite June (Shirley MacLaine), despite the latter's threat that she would drop Blaine's sponsorship if he tried to add Kurt to the event. Though June looked angry for much of the duo's performance, her expression softened and eventually joined the pair's fun song and dance number.

Back in April, however, "Glee" co-creator Ryan Murphy told a small group of reporter that the final season would feature a major time jump, E! News reported.  So perhaps, Kurt and Blaine broke up after the events last season.

Dave was last seen in the 17^th episode of the show's fifth season, in which he was part of Rachel's (Lea Michele) pre-Opening Night dream sequence. The character made its debut in Season 1's "Mash Up" as a generic, slushie-throwing jock whose hatred of the New Directions stemmed from his own struggle with his sexual orientation and same-sex attraction to Kurt, TVLine reported.

Then in Season 3 Karofsky attempted suicide after his crush on Kurt was revealed to his classmates at his new school. Kurt visited him in the hospital and helped him visualize a future with a great job as a sports agent, a loving husband, and an adorable child of his own. In the end of the scene, the two have agreed to become friends.

Since his last appearance in Glee, Adler has been recurring on ABC Family's recently renewed teen/family drama series "Switched at Birth."

"Glee" returns midseason on Fox.