By Toby Prince
The Argentina skipper missed training with Barca early on Friday, with the club citing “personal reasons”, as speculation grew that Antonella was due to give birth.
Matias has since said via Twitter that the couple have indeed welcomed a second son who, despite earlier reports in Spain, will be named Mateo, not Benjamin.
“Well people, Mateo has just been born, he’s beautiful. We’ll give you more details later, now to enjoy it! Thanks everyone!” wrote Matias.
Messi and Antonella’s first child, Thiago, was born on November 2, 2012.
The Argentina captain remains in contention to face Atletico Madrid on Saturday.
“Messi is available although he didn’t train,” Barcelona head coach Luis Enrique told reporters on Friday. “He is on the list. The club gave him permission not to train for personal reasons.”