The correct answer to this question is Michael and Calum. They are members of the band 5 Seconds of Summer. The band is also known for its abbreviation 5SOS. They started as YouTubers. During 2011 and 2012, they would post themselves doing covers of songs. Their first cover was to the song Please Don't Go by Mike Posner. From there, they went on to do other covers and gained attention from labels.
This helped them gain their deal from Sony. From there, 5 Seconds of Summer released their first album. It had little promotion, other than social media ads, but was able to chart third on the Australian iTunes charts. From there, they have gone on to tour all over the world, and release follow up number one albums.