A few fans even got a kiss!
It's no secret the teenage girls who make up the majority of 5 Seconds of Summer's fans are pretty obsessed with them.
So when the guys stopped by Jimmy Kimmel Live! Thursday night for their first American talk show appearance, Kimmel -- television's reigning prank king -- couldn't resist having some fun with just a few of the hundreds of girls who lined up outside the studio.
A producer explained to the chosen girls that they were trying to break a record of some kind or another, and, one by one, had the young women face a television screen and talk about why they love the band. But then, of course, the guys showed up onscreen -- and wanted a kiss. Naturally, because this is late night television, there was a twist.
Check it out below (and ponder just how jealous those girls' friends are going to be that they took selfies with the band):