Screen grab of the video Messi posted of his son Mateo singing

Barcelona's Argentine legend Lionel Messi entered the highly-charged drive by Catalonia for independence on Friday when he posted a video on social media of his child singing in Catalan. The clip on Instagram shows Messi's son Mateo, two, singing a nursery rhyme in the regional language. Among the flood of comments triggered by the post was one from Messi's teammate, Gerard Pique.