RANKED: The 25 Greatest Pop Vocalists of All-Time

23. Justin Bieber

Image Source: businessinsider.com

Justin Bieber was discovered on YouTube in 2008, and is now one of the most famous pop singers of all-time. He made history in 2009 when seven songs from his debut EP made the Billboard charts. Although he was known as a teenage heartthrob, his vocals are what really put him at the top.