aRihanna has within the last few minutes toppled Lady Gaga to become the most popular female star on Facebook, according to Famecount.com the social media statistics service. Rihanna edged past at almost exactly 4pm GMT with both stars at around 40.5m fans, and continues to pull ahead, with her Facebook fan base growing by around 100,000 per day. Only one person, Eminem, on 43m fans, now stands ahead of the R&B diva.

The achievement marks a spectacular year for Rihanna, who has seen her social media fame explode following the release of Loud last year. In February this year, Rihanna became the fourth artist in history to achieve 1bn YouTube views and is now the third most viewed star on the network with almost 1.4bn views, having overtaken Eminem in May. Last week Rihanna became the 13th person in history to achieve 6m twitter followers. And just a few days ago, Rihanna achieved the landmark of 40m Facebook fans, marking the occasion by posting '40 mil! 1 LOVE 'RihannaNavy'.

On an aggregated basis, according to Famecount's rankings, Rihanna is now the third biggest social media star in the world, just behind Lady Gaga and Justin Bieber.

The question now becomes, can Rihanna make it all the way to the top? Eminem is currently 3m ahead on Facebook, but Rihanna is faster growing on the network, and she remains the fastest growing star in the world on YouTube ' thanks to her controversial video 'Man Down' which has now racked up more than 40m views. Meanwhile her fame offline continues to build as Rihanna confirmed earlier this week that she will become the new face (and body) of Emporio Armani lingerie.

If she can maintain momentum Famecount may one day be celebrating a new leader in its overall ranking of social media fame.