Justin Bieber gains 6 million Twittter followers in 4 months This is how it's done people: In March, Justin Bieber had 18 million followers on Twitter. Four months and a bestselling album later, that number has climbed to 24.3 million. Only one other person has broken the 24 million barrier on the social media site: Lady Gaga, who currently has 26.5 million followers. Most of the top 10 most followed people on YouTube are music stars. They include Katy Perry, Rihanna, Shakira and Britney Spears. Barack Obama is the only other male on the list. He has 17 million followers. Bieber hit the 24 million milestone last week and celebrated the moment with a tweet: "from a town of 30,000 - on my 18th bday we hit 18 MILLION...and now 4 months later we are at 24 MILLION BELIEBERS!!! #TEAMBIEBER GOES HARD!" Although Bieber's success on Twitter is impressive, the Canadian heartthrob truly excels on YouTube. Bieber's video for the song "Baby" is the most watched video of all time on YouTube, with more than 750 million views. And the videos on his Vevo channel have been viewed more than 2.6 billion times. YouTube even figures into Bieber's rise to fame. His manager Scooter Braun discovered him by watching Bieber performances on YouTube. Lady Gaga has a little bit of catch up to do with him there -- videos on her Vevo channel have been viewed only 2.2 billion times. Bieber's latest album, "Believe," was released June 15 and hit No. In the United States, the album had the biggest debut of the year, selling 374,000 copies in the first week, according to Nielsen SoundScan. Facebook's new gay wedding icons Happy Birthday Justin! A look at Bieber's $100,000 electric car