5SOS rock New York

Five Seconds of Summer. Picture: Charles Sykes/Invision/AP

Five Seconds of Summer have taken over New York - the Aussie rockers packed out Rockefeller Plaza for a live performance on a US morning show.

5SOS performed their hits Amnesia and She Looks So Perfect, pulling in one of the biggest crowds the show has ever seen.

Fans from across the US had been camping out on the streets since last week to make sure they bagged a good spot in the audience for the gig, according to NBC's Today Show.

The boys from western Sydney admitted the experience felt surreal.

"Seriously, this is the most incredible thing that's probably ever happened to us. Right now. It's amazing," drummer Ashton Irwin told the hosts, who later declared the crowd was bigger than the numbers One Direction attracted in 2012.

"It's definitely not another day at the office," Irwin added.

5SOS announced their first headline tour of Australia and New Zealand last week, including a show at Perth Arena on June 29.

The band have quickly won over the hearts of their fans who came out in force to buy their recently released self- titled album, which rocketed to No. 1 on the iTunes charts in 71 countries, including Australia.

They will play at the MTV Video Music Awards in Los Angeles later this year and have just been announced among the acts at this year's iTunes Music Festival in London.