LONDON—Meet the king of the sporting Twittersphere: Brazilian football superstar Kaka.

The Real Madrid midfielder on Wednesday became the first athlete to amass 10 million followers on the social networking site.

"Thank youuuuu. To celebrate I'll make a twitcam" wrote the 30-year-old Kaka, who at the last count had 10,012,862 Twitter fans.

He's nowhere close to Lady Gaga and Justin Bieber — who each have more than 20 million followers — but it's not a bad haul for a player whose career appears to be on the wane after making himself a global icon in a golden six-year spell at AC Milan in Italy.

Kaka describes himself as a "Christian, husband and father who loves football" and tweets in English, Spanish and Portuguese.

On this side of the pond, former NBA star Shaquille O’Neal has more than 5.5 million followers, while the Miami Heat’s LeBron James checks in at 4.3 million. New England Patriots receiver Chad Ochocinco tops football players with nearly 3.4 million followers.