They’ll now play Hammersmith’s Eventim Apollo for a second night on 21st July.
They’re playing London, Glasgow and Manchester.
It’s the second track from his upcoming album ‘Sleepwalkers’, out February 9th.
Chvrches, Wolf Alice, The Menzingers and Manchester Orchestra are also on the bill.
Fallon is expected to release his new solo album early next year.
‘Painkillers’ is due early 2016 alongside some live dates, with more to follow.
His band, The Gaslight Anthem went on hiatus earlier this year.
After a run of European dates, the band are “taking a break.”
Playing one after another on the Reading & Leeds main stage, the bands have squeezed in an extra show.