Currently in the middle of a national run, US punk legends Unwritten Law have announced they'll be performing an impromptu free show in Melbourne next week.

To make the deal even sweeter for fans, stalwart local outfit 28 Days will join the band at the Bendigo Hotel show on Monday, 12 December, as will Phat MeegzEthan Del Carmen.

"Yeah it's real mates. We're opening the doors at 4pm," the Facebook event page reads.

"We'll post the band playing times closer to the event. Free entry, but get in quick!"

For more details on the show, check out theGuide.