Messi's wife Antonella made the announcement publicly via Instagram.
He's already hit 44 hat-tricks in his glittering career, and it looks as though Lionel Messi is already well on his way to hat-trick number 45, although this one is somewhat different from the rest.
It comes after the Argentine superstar's wife, Antonella Roccuzzo posted on Instagram to confirm that the couple are expecting their third child.
Roccuzzo posted a picture of Messi and their two sons, Mateo and Thiago, with their hands on her stomach with the caption "Familia de 5", which you probably don't need me to tell you translates as "family of 5".
The news caps an eventful week for Messi, who hit a hat-trick to guide Argentina to the World Cup with a 3-1 in Ecuador, further cementing himself as a national hero, before playing the full ninety minutes of Barcelona's 1-1 draw with Atletico Madrid on Saturday evening.
With Messi for a father, you feel there may be a rather clear career choice for Barcelona's youngest trio in a few years time.