In the upcoming episode of "Glee" Season 4 Episode 21 "Wonder-Ful," fans can expect to see familiar faces returning to McKinely High as the show pays tribute to the great Stevie Wonder.

In the sneak peek video we see New Direction alumini Mike Chang played by, Harry Shum Jr, Mercedes Jones played by Amber Riley, and Kurt Hummel played by Chris Colfer return to Lima to participate in the glee club's Stevie Wonder week.

According to Hypable.com  in the sneak peek Darren Criss who portrays the character Blaine, reveals that this episode focuses on dreams that were a long time coming such as an album for Mercedes, "Funny Girl" for Rachel, and, hopefully the return of Klaine.

In the upcoming episode fans can expect Brittany's future to be resolved, "Glee" star Chord Overstreet told The Hollywood Reporter that "Brittany's story line will conclude and you'll figure out where she's going."

"She comes in and out of MIT and goes back and forth and you'll see where she's headed and what's going to happen with her. It'll be an emotional episode but it will be fun."

Brittany's departure from the show will be quite coincidental since it is rumored that Heather Morris who plays the character is pregnant.

Overstreet also reports that his character Sam will be there for Blaine when he decides to pop the big question to Kurt.

In an Interview with The Hollywood Reporter Overstreet confirmed that none of the seniors would be graduating this year because the Glee Season 4 finale, Episode 22: "All Or Nothing," will not be focused around the end of the school year.

Overstreet said, "the final two episodes are more toward gearing up for Regionals."

To listen to the song list from the upcoming episode sang by your favorite "Glee" cast members, CLICK HERE.

Make sure you catch "Glee" season 4 episode 21, "Wonder-Ful" on Thursday, May 2nd on Fox.