Fox has released a new sneak peek for the upcoming episode of Glee, which is titled What the World Needs Now and features the 700th musical number performed on the show.

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The sneak peek features cast members Lea Michele (who plays Rachel), Becca Tobin (Kitty), Darren Criss (Blaine) and Sam (Chord Overstreet) discussing what is ahead for this episode.

"This episode is very exciting," Tobin says in the video. "Kurt [Chris Colfer] and Rachel introduce the lesson for the week as Burt Bacharach. We're five weeks away from another competition. Mercedes [Amber Riley] comes back to be our mentor."

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With the Rachel-Sam relationship heating up, Mercedes discusses the dynamic with Rachel, ultimately giving her the go-ahead.

"And then there's a little like love triangle between Mercedes, Sam and Rachel. She eventually gives her blessing," Michele says.

As mentioned above, this episode will feature the show's 700th musical number, which is Bacharach's What the World Needs Now. Overstreet says in the video that he is hoping for some cake in celebration while Criss says that Bacharach is one of his personal favorites.

The performance will apparently serve as a tribute to Santana (Naya Rivera) and Brittany (Heather Morris), who will be getting married.

"We're singing for Santana and Brittany, giving them a little love," Michele says, to which Tobin adds, "And at the same time inviting ourselves to their wedding."

This is sure to be another emotional episode of Glee as the series winds down to its final episodes.

Glee airs Fridays at 9 p.m. ET/PT on Fox.

Watch the sneak peek for the next episode of Glee below:

Tags: Glee television fox