Lionel Messi's Girlfriend Gives Birth to a Son (Reuters) - World Player of the Year Lionel Messi has become a father for the first time following the birth of his son Thiago on Friday. "Leo Messi is a father," his club Barcelona said in a brief statement on their website (www.fcbarcelona.com). This Friday afternoon Antonella Rocuzzo, the Argentine star's girlfriend, gave birth to Thiago Messi, the couple's first son. Messi, 25, added on his Facebook page: "Today I am the happiest man in the world, my son has been born. I thank God for this gift. Thanks to my family for the support. A hug for everyone. All being well, forward Messi should still be available for Saturday's La Liga match at home to Celta Vigo (1700 GMT), Barca coach Tito Vilanova said earlier on Friday. Writing by Iain Rogers in Madrid, editing by Mark Meadows