5 Seconds of Summer drummer Ashton Irwin reckons the band's rise to fame is "insane".

The Australians hit the big time last year with their chart-topping self-titled debut album.

Their upwards trajectory occurred before that, however, when they supported One Direction on tour.

Speaking on Twitter on Thursday (March 12), Irwin suggested that he still can't believe how far the pop-punks have come.

Posting alongside a comparison photo of low-key fan performance and a stadium show (pictured below), Irwin said:

"Insanity. I love you all so much."

5 Seconds of Summer meanwhile will embark on a headline world tour this year.

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