Justin Bieber has become the first artist to hit 50 million subscribers on his YouTube channel. The singer, who got his start on the platform back in 2007, holds steady as the most-subscribed artist on YouTube. The record number of subscribers isn't the only milestone he hit. The first episode of Justin's new YouTube Original series, Justin Bieber: Seasons, is now YouTube Originals’ most-watched debut episode to date, reaching over 97 countries. The series unveiled its fourth episode yesterday, focusing on Justin’s relationship with wife Hailey Bieber. Justin Bieber: Seasons is documenting Justin's return to the spotlight and the making of his new album, Changes, due out February 14.