5 Seconds of Summer think Zac Efron has a "great face".

The Australian boyband are currently promoting their self-titled debut album, which includes hit single She Looks So Perfect. Part of their advertising stint involved stopping by BBC Radio 1 in London, which often has A-list stars in for interviews during its breakfast show with host Nick Grimshaw.

One guest who has previously graced the studio is Zac, and the 5 Seconds of Summer boys - Michael Clifford, Luke Hemmings, Calum Hood and Ashton Irwin - had nothing but praise for the star.

"He does have a great face... he's a great actor as well. I mean what a guy, Zefron, the Fron!" they gushed.

"I watched That Awkward moment," one of the lads quipped, while another added, "I'm a big [Charlie St. Cloud] fan, is that what it's called?"

Upon the band's arrival there was a hoard of female fans standing outside the building. Now they are rising to fame, the boys still can't get their head around the attention directed at them.

"It's weird, I don't know, it is weird. We still don't understand, it doesn't really compute to the people who like our band.

"You never really get used to it," they added.

"It is a weird thing. If I met Dave Grohl, he doesn't have Twitter which annoys me every day, but I would just say, 'Dave, be my friend.'"

The quartet found success on YouTube after British pop sensations One Direction discovered their video covering Wheatus' Teenage Dirtbag last year. They went on to support the You & I hitmakers during the Australian spell of their Take Me Home Tour.

Now mingling with big musicians, 5 Seconds of Summer have been lucky enough to spend time with some of their musical idols.

"Yes we have [met our heroes]. Over the last year and a half we've had the change to hang out with the people who've influenced us and to pick up their instruments, like the Madden brothers from Good Charlotte... it's been absolutely awesome.

"They do go as pairs," the band laughed about the Madden brothers Benji and Joel.