File picture of Lady Gaga. The US pop star is the most-followed person on Twitter, hitting over 20 million

Pop diva Lady Gaga has become the first person with more than 20 million followers on Twitter.

A 20 millionth "Little Monster," as calls her fans, signed up to follow her Twitter feed over the weekend.

She had 20.12 million as of Monday for her @ladygaga account.

Teen pop idol Justin Bieber was next with 18.11 million followers of his @justinbieber feed.

Rounding out the top five were three other singers: Katy Perry with 15.75 million followers, Shakira with 14.56 million and Rihanna with 14.49 million.

US President was in eighth place with 12.84 million followers of his @barackobama account.