Fontaines D.C. capped off their lauded UK Tour last night with a headline show at Alexandra Palace in London – which included the debut of a currently unreleased song, in front of the 10,000-strong audience.

Footage from the gig was uploaded to YouTube under the title 'I Love You' by the Fontaines D.C. fan group, What's Really Going On.

Whether the new track will feature on their upcoming third album – the follow up to A Hero's Death – remains to be seen. In a recent interview with NME, Fontaines D.C.'s bassist Conor Deegan said the next album will contain "quite poppy" song – but was also described by their manager as "the darkest shit" they've ever written.

The Grammy-nominated band were joined on their UK tour by acclaimed Cork act The Altered Hours.

Take a look at Fontaines D.C. performing their new track below:

See some of the reactions to the gig below:

Fontaines DC last night at Alexandra Palace.

Beware of the Risen People. ✊️ pic.twitter.com/U8Q29lMoUD

— Tom Raeside (@Raeside_Tom) October 28, 2021

Fontaines DC at Alexandra Palace tonight. 10000 people! Mad!

Was I at the front? Of course I was at the front... @fontainesdublin pic.twitter.com/JiQ3vfJfvz

— Jez🤍💙💛💙🤍 (@madmidweeker) October 27, 2021

After a long day talking about sh💩t what better way to cheer yourself up than the @fontainesdublin 😀 pic.twitter.com/cESC9Kszzi

— Feargal Sharkey (@Feargal_Sharkey) October 27, 2021

Round 1 vs Round 8.

150ish people - 10,000 people.

All in 2 years. What a band @fontainesdublin pic.twitter.com/eUEiDavmSj

— JFK. (@JayKelly00) October 28, 2021

★ ★ ★ ★ ★ - “This is the most exciting band to come out of Ireland in decades”@Willjhodgkinson has given @fontainesdublin's Ally Pally headline show a 5-star write-up in @thetimes. Check out the review in full here:https://t.co/r3nkK1zdZL

— Prescription PR (@prescriptionpr) October 28, 2021

4 years ago @fontainesdublin played to 30 people in Mike the Pies. Tonight they play to 10000 in Alexandra Palace. #FontainesDC #fontaines #mikethepies #idratherbeinmikethepies pic.twitter.com/vUTUtzNeDP

— MikethePies (@MikethePies) October 27, 2021