Dave Grohl has made it well know: he is an ABBA fan! The Foo Fighters' frontman wore an ABBA shirt on stage when he joined Paul McCartney at Glastonbury. And in response, Benny Andersson said thank you by playing "Learn To Fly" in his Foo Fighters shirt!
Also, very cool of Dave to have the T on his hand for Taylor Hawkins.
Well done, everyone!