Stars including Justin Bieber, Kim Kardashian and Rihanna have lost millions of followers on after bosses of the social networking website launched a crackdown on fake accounts.

Instagram bosses have purged millions of accounts from the site as part of a huge project to rid it of spam and fake profiles, and the crackdown has cost many celebrities huge numbers of followers.

Bieber has lost around 3.5 million followers, while reality Tv star Kardashian lost 1.3 million and Rihanna shed around 1.2 million. Other stars to have their numbers decline include pop star Ariana Grande, who now has 1.5 million fewer followers, as well as Selena Gomez, Bruno Mars and Kendall Jenner.

A statement released by Instagram bosses reads, "We're in the process of fixing an issue that incorrectly includes inactive or fake accounts in follower/following lists. We want to maintain the best possible experience on Instagram, so we do our best to remove spam, fake accounts and other people and posts that don't follow our Community Guidelines. As we remove these accounts, some people may notice a decrease in their follower/following counts."