'Glee' is back with a groovy new episode, which pays tribute to 'Saturday Night Fever,' and now Gleeks can get a sneak peek at the cast's performances of 'Disco Inferno' and 'You Should Be Dancing.'

Mercedes (Amber Riley) heads up the Trammps cover with rich soul, while getting a little back-up dancer help from Brittany (Heather Morris) and Santana (Naya Rivera). The girls begin the song in the halls of William McKinley, before moving into the choir room, which has been transformed into a mini disco.

Meanwhile, Blaine (Darren Criss) surrenders to a daydream during class in which he kicks off the Bee Gees classic under a fabulous mirror ball. He's joined by Brittany and Mike (Harry Shum, Jr.) as they make their way through the halls and to the auditorium stage to show off their impressive dance skills.

Six additional songs are expected to be performed on Tuesday's show, including 'Night Fever,' ‘How Deep Is Your Love,' ‘If I Can’t Have You,' 'More Than a Woman,' 'Boogie Shoes,' and, of course, the iconic 'Stayin' Alive.' All of the songs from the tribute show appeared on the soundtrack for the 1977 film, starring John Travolta and Karen Lynn Gorney.

Watch Amber Riley Perform 'Disco Inferno' on 'Glee'

Watch Darren Criss Perform 'You Should Be Dancing' on 'Glee'