The pop-punk world has just come full circle.

5 Seconds of Summer hit the stage in Irvine, California, for the latest stop of their Rock Out With Your Socks Out Tour, and decided to invite some special guests in the audience to join them on stage.

Oh, those concert goers just happened to be Joel and Benji Madden of Good Charlotte. After enjoying some of the show from their seats, Luke and Michael asked their "first ever favorite band" to come up on stage for a little jam session.

Michael told the crowd that they were going to perform the band's 2003 hit, "Girls & Boys," which instantly cued the nostalgia and the insane screams from the crowd.

Luke and Joel traded vocals, while Benji, Michael and Calum jammed their guitars. Of course, Ashton killed it on the drums. Once the song wrapped, the guys exchanged hugs, and Joel decided to hump Calum's leg because why not?

This collaboration isn't be too surprising since 5SOS have become pretty good friends with Joel and Benji, who co-wrote their latest single, "She's Kinda Hot." Benji and Joel also lent their co-writing hands to 5SOS's "Amnesia," which they covered at one of their own concerts last year.