"Wild time last night at Open'er Festival in Poland rocking out hard with pals"
The rock star was previously spotted at Glastonbury last week
Taylor Hawkins' son Shane also performed 'This Is A Call' with the band
Swift has since seemingly responded
Check out photos, footage, the setlist and more from the mammoth gig here
Support at tonight's gig comes from Shame and Wet Leg
They also broke out tracks including ‘Skin And Bones’ and ‘Show Me How’ for the first time this tour
Dave Grohl sticks to his old tricks as the Foos kick off their most ambitious UK stadium tour to date
"It was super raw", Grohl said of his original demo
The song was "partially written and demo’d during home studio sessions years ago — but ultimately left unfinished"