5SOS originally formed on 3rd April 2011, however Ashton didn't join until December 2011.
Before the band was formed, the boys posted videos of themselves performing popular songs on Luke's YouTube channel.
Their success on YouTube caught Sony's attention, who signed the band to a publishing deal with Sony ATV Music Publishing in 2012.
Luke, Michael and Calum, all attended Norwest Christian College in Sydney, which is where they first met.
Their first gig was in front of only 20 people!
5SOS doesn't have an official fandom name, but their fans either call themselves the 5SOSFam.
The band said that they pretty much hated each other before they got together, but now they're like brothers.
The boys' biggest musical inspirations are Blink 182, All Time Low, Ed Sheeran and Green Day.
5 Seconds of Summer's manager is called Adam Wilkinson, his Twitter is @adam_wilkinson.
The boys have admitted that they like to follow people that have 5SOS in their Twitter name or bio.
They say one of the best parts about being in the band is meeting their fans.
Ashton Irwin is the oldest member of the band.
The band once had to stop and busk on the streets, because they didn't have enough money for petrol to get home!
Whilst busking at Hyde Park in Sydney, a fan gave 5SOS a giant poo toy!
The boys thought about auditioning for X Factor in but they didn't want to be known as 'that band from X-Factor'.
Whilst recording the Unplugged EP, all the members of 5SOS were sick, but they didn't let that stop them!
On 8th of March 2012 #5secondsofsummer trended on Twitter for the first time worldwide.
Louis Tomlinson from One Direction Tweeted a link to their YouTube song, 'Gotta Get Out' in 2012.
Their first single called "Out of My Limit" was released on 19th November 2012.
Out of My Limit received over 100,000 views on YouTube within the first 24 hours of it being released.
Originally, Out of My Limit was called "Over the Limit" but had to be changed because it sounded like the song was about alcohol.
Niall Horan Tweeted a link to 5SOS' Out of My Limit video on YouTube on its release date.
Because the One Direction boys were all massive fans, this led to 5SOS supporting thier Take Me Home Tour which started on 23rd February 2013 at the O2 Arena in London.
5 Seconds of Summer supported One Direction for shows in the UK, USA, Australia and New Zealand.
Harry Styles "pranked" the 5SOS boys on tour by running into their room, throwing their fruit at them, and tipping tables over as he ran off, oh and did I mention, Harry was completely nude whilst doing this! Michael said the event was "traumatizing".
5SOS have a bus named Gus - it rhymes!
The boys brush their teeth together before every show.
Michael came up with the band's name in a maths lesson; initially the other boys all hated it.
They have written and recorded over 100 songs and have already written with McFly and Busted.
Since 5SOS went to Blackpool, they fell love with English accents.
5sos are going to write with All Time Low in the near future.
Their acoustic EP 'Unplugged' reached number three on the iTunes charts in Australia. It also reached the Top 20 in New Zealand & Sweden.
The boys rarely wear matching socks!
5 Seconds of Summer have their own record label called 'Hi Or Hey Records' in partnership with Capitol Records.
In 2013, they won two awards which were Channel V's, Oz Artist Award, and an MTV award for Breakthrough Band.
In early 2014, they won the Nickelodeon Kids' Choice Awards for Aussies' Fave Hot New Talent.
In March 2013, 5SOS went paint-balling with Zayn Malik and Louis Tomlinson in Doncaster, England.
Michael said if the band wasn't called 5 Seconds of Summer, it would probably be called 'Bromance' or 'The Powerpuff Blokes'.
On 5th February 2014, 5 Seconds of Summer listed their worldwide debut single "She Looks So Perfect" for pre-order on the iTunes Store.
Within two days, 'She Looks So Perfect' reached the number one position in 39 countries including the UK, Australia, Spain and Brazil.
The official music video for She Looks So Perfect was directed by Frank Borin, and since its release on YouTube on 24th February 2014, it has been watched over 139 million times!
5SOS celebrate Record Store Day by giving out cassette tapes to music shops around the UK, which were free for fans who said the password "She Looks So Perfect".
The cassette also includes a song called Pizza, which was never heard by fans before this.
"Don't Stop" is their 2nd single with Capitol which was released on 16th June 2014.
The director of the 'Don't Stop' lyric video said 'The red-haired girl in video is based on their fans.
Their official twitter is @5SOS.
