Lady Gaga has become the first person to reach 25 million Twitter followers; knocking out Justin Bieber by more than 2.5 million.

The controversial pop icon celebrated with her fans by tweeting, "#25milliontweetymonsters wow! I'm officially feeling like the luckiest girl in the world today."

(Photo: AP Images / PictureGroup / Frank Micelotta)Lady Gaga performs onstage at the 2011 Robin Hood Foundation Annual Gala at the Jacob Javits Convention Center on May 9, 2011 in New York City.

The landmark for Lady Gaga came as another iconic figure was being celebrated throughout the world – Marilyn Monroe would have celebrated her 86 birthday June 1, 2012.

Gaga decided to take part in those celebrations herself by posting a photo of herself dressed up as Marilyn Monroe; with blonde hair and thick lip stick on.

She wrote alongside the photo posting, "#HappyBirthdayMarilyn They'll never take our blonde hair and lipstick."

Lady Gaga has been a controversial figure in recent months as she embarks on the Asian leg of her world tour. She was forced to cancel one of her shows last week due to security risks and her shows have been protested against in pretty much every nation she has gone to so far. The Muslim majority countries are offended at the content of her shows, with some calling them immoral and pornographic.

However, the controversy surrounding her tour has only gone to surge her Twitter followers, and Gaga is now the most followed person in Twitter. Well ahead of her competition; Justin Bieber has only 22.5 million, followed by Katy Perry with just over 20 million, and Rihanna with just under 20 million.

Singers generally make up the most followed people on Twitter. However, United States President Barack Obama breaks that trend by landing in at number 7 with 16 million Twitter followers. Kim Kardashian also makes the top 10, even though she is not a singer.

The Top 10 in Twitter followers are:

Lady Gaga – 25 million

Justin Bieber – 22.5 million

Katy Perry – 20.4 million

Rihanna – 19.7 million

Britney Spears – 17.2 million

Shakira – 16.3 million

Barack Obama – 16 million

Kim Kardashian – 14.8 million

Taylor Swift – 14.5 million

Nicki Minaj – 12.2 million