• JUSTIN BIEBER photo | Justin Bieber

Credit: Omar Reyes/Landov, FameFlynet

Published: Thursday August 08, 2013 06:00 AM EDT

2013

JUSTIN BIEBER

Then: Bieber's ascent to superstardom proved swift after Usher signed the YouTube sensation to his record label in 2007 and his best-selling 2009 debut album, My World, scored the 15-year-old an invite to that year's MTV VMA Awards.
Now: The 19-year-old has experienced some growing pains: After receiving rave reviews for his third album, he embarked on a world tour in 2013 that's seen its fair share of problems – and he's endured an on-again, off-again relationship with Selena Gomez.