still shooting; It was initially filmed in parallel with that episode, which continued through October 14, 2011, and also with the seventh episode, which began filming on October 13, 2011. This episode marked the 300th musical number Glee has filmed, which was a mash-up of two Adele songs: "Rumour Has It" and "Someone Like You", with lead vocals by Amber Riley and Naya Rivera. The performance was filmed with great fanfare "in front of an audience of press and crew members" on October 26, 2011, and included a press briefing afterward. Riley revealed during the briefing that she suggested the idea that she perform Adele to co-creators Brad Falchuk and Ryan Murphy after finding out that Adele was hoping Riley would sing her music on the show: "Someone actually e-mailed me a video of Adele saying that she wanted me to sing her song, so I e-mailed it to Brad and Ryan." The episode was to contain a flashback to a sixteen-year-old Sue, played by Colby Minifie, singing the title song of the musical Oklahoma! in a scene that would have explained Sue's antipathy to music in the schools. Series co-creator Ian Brennan said "we wanted to show that Sue at one point had Broadway dreams", and Lynch reveals, "Will tells Sue, 'Poor little Susie Sylvester was told she wasn't good, and now she's got to punish the world.' Like a lot of angry people out there, Sue's a wannabe." However, the scene was not broadcast because it was, according to Murphy, "too long for the episode"; he also stated that the footage, with the title "How Sue Sylvester Became a Bitch", would be released in the future, "either as a DVD extra or online". Three other mash-ups beyond the Adele one are performed in the episode: a Hall & Oates mash-up of "I Can't Go for That" and "You Make My Dreams" performed by New Directions, a mash-up of Lady Gaga's "You and I" and Eddie Rabbitt and Crystal Gayle's "You and I", performed by Morrison and Menzel, and one of Pat Benatar's "Hit Me with Your Best Shot" and Blondie's "One Way or Another", performed by competing glee clubs New Directions and the Troubletones. Van Halen's "Hot for Teacher", performed by Mark Salling, is also included. Recurring guest stars appearing in the episode include teacher Shelby Corcoran (Menzel), Kurt's father and new congressional candidate Burt Hummel (O'Malley), Principal