Billie Joe Armstrong of Green Day played himself in a super fun cameo in 'This Is 40,' the latest Judd Apatow coming-of-middle-age film starring Paul Rudd and Leslie Mann. Sadly, the hilarious scene landed on the cutting-room floor. You can still watch it, though, as it's turned up online.

Armstrong, who's been in rehab and dealing with personal issues the past few months, plays a snobby and pretentious version of himself. It's not exactly hard to play yourself, but Armstrong nails it, showing his snooty side in the hilarious scene.

In the clip, he visits Rudd, a music industry exec, to share his idea of mixing Norwegian death metal with Belle and Sebastian. "It's sort of music you can cry to but also maybe burn a church down at the same time," Armstrong says. "I kind of want it to sound like two different radio stations going off at the same time in a white supremacist's car."

The proposed project is all about creating violence, and it has nothing to do with Green Day. In fact, Armstrong won't use his own name, and he refuses to tour behind it, since it's "impossible to play live and too dangerous." It's also completely impossible to market and promote.

The funniest line of the scene? "I actually sell too many records, so I am trying to change that by doing a side project," Armstrong says. Oh, irony!