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Cristiano Ronaldo is the world's second most-followed person on Instagram.
Earlier this year, financial services firm Deloitte released its annual Football Money League, charting the massive revenues of Europe's biggest football clubs.
As the wallets of the continent's biggest teams continue to grow, so too do their online presences.
Social media has become a crucial part of the way the largest clubs connect with their fans around the world, with some even hosting foreign language Twitter accounts.
Social media is also increasingly driving revenue for clubs as brands target players with large followings for sponsorships.
There is still some disparity, though, between the clubs with the most money and the clubs with the most fans (on social media, anyway).
Scroll down to see who are the most popular teams from Deloitte's rich list, ranked in ascending order of combined followers on Facebook, Instagram and their biggest Twitter page - rounded to the nearest hundred thousand.