Billie Joe Armstrong shares his reaction to rewatching the episode of is full of pop culture jokes and musical references, often thanks to movie-obsessed Michael Scott and former college a cappella group member Andy Bernard.

One such reference comes in season 6, episode 13, "Secret Santa," which aired on December 10, 2009. The episode centers on Dunder Mifflin's Christmas party, which occurs as the staff learns the company may be sold. However, Michael is more focused on the fact that Jim (John Krasinski) agreed to let Phyllis (Phyllis Smith) play Santa at the party, a role he usually throws his heart and soul into. This conflict leads to the complete destruction of the event, but once the group learns their jobs are safe, they begin to feel the Christmas spirit once more. This is shown in a scene where Dwight (Rainn Wilson) takes to the karaoke machine to belt out the 2004 Green Day track "Boulevard of Broken Dreams."

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On a recent episode of the The Office's "Secret Santa" episode. Fischer revealed she is friends with Armstrong, who is Green Day's lead singer, and had him submit an audio clip summarizing the plot of the episode. She later unveiled an additional surprise clip where the musician reacted to hearing the Green Day song at the end of "Secret Santa." Read Armstrong's full quote below:

I was binge-watching The Office for the first time, and I was watching that episode and then all of a sudden the song came on and I was completely taken by surprise. And like, I think my face started to get red and Andy...he started singing harmonies, which was almost like — we do have a musical for American Idiot, and he sang the same exact harmony that's in the musical. So it was, it was good.

The Office Secret Santa Episode Jim and Pam

While Armstrong almost certainly knew at the time that The Office would be using his song, that fact might have been easier to forget than many people think. He most likely was not directly involved in the contract negotiation for the sitcom to license the song. Additionally, The Office was just one of many projects in that era using the band's music. The long list includes The Vampire Diaries, Waiting for Superman, Get Him to the Greek, and even The Simpsons Movie, which had Green Day play themselves performing the Simpsons theme song.

It certainly seems like it was surreal for Armstrong to revisit The Office. It would have been doubly strange to hear his song considering he was in the middle of a binge-watch, meaning that he had recently seen over 100 episodes of the series that were completely Green Day free. Armstrong's reaction clearly shows how much the music still means to him and how honored he is that shows like The Office use it.

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Source: Office Ladies (via Mashable)