One Direction's Niall Horan and teen sensation Justin Bieber appear to have struck up a friendship and spent part of this afternoon chatting publicly via Twitter.

Earlier today (July 18), the 'Boyfriend' superstar sent a message to Horan asking "what's up bro" to which he replied:

"Ari dude! Nothin much! How was australia dude? Great spot down there!"

Bieber told him that he's been enjoying his time down under and quizzed him on the whereabouts of One Direction: "Australia was amazing now headed to NZ, where u headed next?"

The Irish heartthrob then explained that his group are hard at work in the studio preparing new material for their second album: "Around here for a while, in the studio ,gettin album 2 ready! New zealand another amazing place."

When Bieber said he was about to begin a flight, Horan added "chat later" leaving fans of both the singer and band member wondering what they might have to discuss.