No, the football player Isco is not known to be a Muslim.
His background is from Andalucia in Spain.
If you want to know which famous footballers are thought to be Muslim, then have a look at this video:
Some of them I know for sure, such as Sagna because I have seen him pray before a game.
Others like Van Persie I know it's false, as he is married to a muslim woman, but is not muslim himself.
And if you're just a fan of Isco...
Then here is one of my favorite compilations of stunning goals and skills he's produced over the years while playing for Malaga, Real Madrid and Spain
So whether he's a Muslim or not, I'm sure you'll agree he's gifted!
