5 Seconds Of Summer underpants-dance at the iTunes Music Festival

If you heard distant screaming of hormonal masses over in England on Sept. 4, that's because 5 Seconds Of Summer performed there during the iTunes Music Festival.

And while the pop-rock quartet's set was a crowd-pleaser — with songs off of their self-titled hit album like “She Looks So Perfect” and “Amnesia” — it was the scenery from the green room that the crew probably drew the most squeals.

“This is a very serious video,” wrote drummer Ashton Irwin on Twitter, as he posted a video of the Aussie band in their underwear getting down to… John Mellencamp?

The full iTunes Music Festival set is below that. 5SOS is on tour now with One Direction with a few additional dates of their own.

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