Foo Fighters Rip Donald Trump For Using 'Hero' Without Permission at Rally

Donald Trump's habit of using famous artists' music at his rallies is about to backfire on him -- that's what the Foo Fighters are saying after he cranked one of their biggest hits ... without permission.

Trump brought out Robert F. Kennedy Jr. -- who ended his campaign and endorsed Trump -- Friday evening in Glendale, AZ while blaring FF's 1997 hit "My Hero," and while the pyrotechnics and music fired up the crowd ... it simply pissed off Dave Grohl and company.

Once the Foo caught wind of the wild scene in AZ, the band sent Trump a clear message: Don't do that!

FF says they would not have granted Trump permission to use their song if his campaign had bothered to ask, but says they'll now take appropriate measures to ensure it doesn't happen again.

Grohl's band promised one more move that's sure to piss off Trump -- it said any royalties generated by Trump's usage of "My Hero" would be funneled to Kamala Harris' presidential campaign.

So, basically, if there's a bump in streaming or purchases of the song in the wake of Trump's AZ rally ... Foo Fighters will donate those funds to team Harris-Walz.

It's a new ploy for an old problem -- previously, Trump has played the late Isaac Hayes' "Hold on, I'm Coming" without permission ... prompting Isaac's estate to file a notice of copyright infringement.

Trump also found himself in hot water with Beyoncé after his campaign posted a video on X showing Donald walking off a plane scored with "Freedom." It was a full troll job, as the song is VP Harris' campaign anthem ... something Bey fully authorized.