5 Seconds of Summer have thanked their fans after hitting No.1 in the UK with their debut single.

The Australian group, who have supported One Direction in the past and are due to do so again this year, reached the top spot on Sunday (March 30) with 'She Looks So Perfect'.

The news seemingly shocked the band, with Calum Hood writing on Twitter: "Wow. Actually speechless. Can't actually put how I feel into words. I love you guys so much. Best thing that's ever happens to me."

Luke Hemmings added: "Number 1 in the UK, I think I'm gunna go cry now. Thank you so much! we did it guys xx."

The band's account meanwhile said: "What a surreal day, you guys are the best! 2 more days America till SLSP! And we are also headed to EUROPE! Goodnight! Xo. P.s did I mention you are all amazing. And we love you."