One Direction picks australian band 5 Seonds Of Summer as support act for World Tour

1D's Louis Tomlinson discovered the YouTube videos of rising pop rockers 5 Seconds Of Summer, who hail from Sydney's western suburbs, and championed them via social media.

5SOS's Luke Hemmings, Michael Clifford, Calum Hood and Ashton Irwin relocated to London to write and record their debut record in December and the 1D lads invited them "to hang out".

Niall Horan dropped by their studio in January while Tomlinson and Harry Styles challenged them to a football match where the Australians were soundly beaten 15 to 2.

Their blossoming bromance turned into 5SOS's big break when 1D personally chose them to join them on the 110-date world tour which kicks off at London's O2 arena on February 23

“We discovered 5SOS on YouTube last year and we all knew straight away they were very special. We’re so excited to have them on the road with us and we know our fans are going to LOVE what these lads do," Horan said.

In just 15 months, the Sydney lads have gone from playing to 20 people at legendary live music nursery, the Annandale Hotel, to performing in front of 1.3 million 1D fans in Europe, America and Australia.